blood pattern analysis case study

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Published: 21 May 2021

Blood pattern analysis—a review and new findings

Prashant Singh ORCID: orcid.org/0000-0003-1340-1789 1 ,
Nandini Gupta 1 &
Ravi Rathi 2

Egyptian Journal of Forensic Sciences volume 11 , Article number: 9 ( 2021 ) Cite this article

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Blood is one of the most common pieces of evidence encountered at the crime scene. Due to the viscous nature of blood, unique bloodstain patterns are formed which when studied can reveal what might have happened at the scene of the crime. Blood pattern analysis (BPA), i.e., the study of shape, size, and nature of bloodstain. The focus of this paper is to understand blood and BPA. An experimental finding to understand blood stain formation using Awlata dye was conducted within the university premises under laboratory conditions. Awlata ( Alta ), an Indian dye used for grooming of women, was used to create fake blood stains to understand the formation of bloodstains with respect to varying heights, and their relation with spines and satellite stains was determined.

When the height of dropping fake blood increased, the distance of satellite stains emerging from the fake blood stains was also increasing. From the experimental finding, it was found that satellite stains were directly proportional to height of blood stain and spines were inversely proportional.

It can be concluded that blood is a vital source of information and when interpreted correctly it can be used as a source of information that can aid in investigations. Thus, a relation between formation of blood stains with relation to height was established. This finding using fake blood stains can help in carrying out future studies.

The study aims to determine the relationship between spines and satellites stains in accordance with varying heights using Awlata dye. It involves creation of fake bloodstains using Awlata dye to determine this relation. The study also seeks to suggest the use of Awlata dye for studying bloodstains for conducting future studies.

Blood is an organic fluid circulating in our body that is essential to maintain life; it includes blood cells and plasma that accounts for approximately 8% of body weight. Blood ranges from 4–5 L (female) to 5–6 L (male). Blood has few bodily capabilities which can be required for its morphological interpretation like specific weight, viscosity, and surface tension (Peschel et al. 2011 ; Bevel and Gardner 2012 ). Viscosity in terms of blood may be described as the pressure of the flow of blood, due to shear stress or extensional stress inside the body (Bevel and Gardner 2012 ). An elastic-like property of a fluid due to cohesive forces between liquid molecules is surface tension (Larkin et al. 2012 ). Blood possesses fluid nature inside the body or when it exits from the body due to an impact/injury (James et al. 2005 ). If there were blood clots in the blood found at the crime scene, it suggests that the victim was exposed to an extended injury (Peschel et al. 2011 ; Bevel and Gardner 2012 ).

Blood can exit from the body as drip, spurt, etc., or can even ooze from wounds depending on the type of infliction/damage. BPA is a type of examination that includes the interpretation of shapes of the bloodstains (James et al. 2005 ). Blood pattern analysis aims to reveal the physical events that might have occurred at the crime scene. These bloodstains can be interpreted by their shape, size, and distribution (Brodbeck 2012 ). The facts acquired from BPA can help in crime scene reconstruction, corroborating witness statements, for the investigative procedure (James et al. 2005 ). If bloodstains at a crime scene are either dried or removed by the assailant, they can still be recovered by spraying luminol. Luminol (5-amino-2,3 dihydro-1,4-pthalazine-dione) can be used to detect the presence of minor, unnoticed, or hidden bloodstains diluted down to a level of 1:10 6 (1 μL of blood in 1 L of solution) which gives chemiluminescence or glowing effect when it reacts with dried bloodstains (Quickenden and Creamer 2001 ).

Luminol solution is usually directly sprayed in completely dark environments, and then UV (ultra violet) light visualizes the sample (blood). The fluorescence obtained is then photographed or filmed. Luminol can be used to identify minor, unnoticed, or hidden bloodstains, and it also has a high sensitivity to old blood or completely dried blood but, unfortunately, luminol can react with detergents, metals, and vegetables to give false-positive results (Barni et al. 2007 ). Sometimes, there are probabilities that the bloodstain recovered had been created using certain substances (dyes/stains) to deceive the investigators. To distinguish whether a sample is blood or not, assays like Kastle-Meyer (phenolphthalein test), Medinger reaction (Leuco malachite Green), and Tetramethylbenzidine test are used, but they cannot satisfactorily confirm blood (preliminary tests). So, for the confirmatory evaluation of blood, Teichmann and Takayama tests are performed to distinguish if the samples were blood or not (Saferstein and Hall 2020 ). It is also very important for the analyst to determine the origin of species of blood (whether human or animal) by precipitin test; this is often necessary to avoid confusion in investigative findings. There are several conditions in which the bloodstain patterns are disturbed/altered and in such cases, no useful information can be interpreted. So, DNA analysis is utilized for providing investigative leads (Saferstein and Hall 2020 ). When the bloodstains are suspected to be from multiple sources, the investigator can often rely on DNA to reveal valuable details about the crime. So, in the case of multiple victims, analysts often use DNA profiling to determine whose blood it was (James et al. 2005 ; Karger et al. 2008 ).

Bloodstain patterns distributed at the crime scene can be used for the reconstruction of an event (Comiskey et al. 2016 ). Before reconstruction, an analyst must have a comprehensive view of the overall picture and use the step-by-step approach to differentiate and analyze the bloodstain patterns and search for the informative points (James et al. 2005 ). It is also required that the investigator must create a hypothesis on the formation of blood patterns due to injuries. Reconstruction can be further improved by the contribution of case descriptions and statements (witnesses/perpetrators) that can provide insights on the sequence of events. Hence, to carry out an effective reconstruction, both casework experience combined with knowledge of injuries should be known (Karger et al. 2008 ; Kunz et al. 2013 ; Kunz et al. 2015 ).

Types of bloodstains

Passive patterns.

It is a type of bloodstain pattern formed due to gravity, patterns like drip stain, flow stain, blood pool, and serum stain are observed. A drip stain is a drop falling without any disturbance that can take a spherical shape without disintegrating into smaller droplets. Bloodstains, depending on the angle, can cause the blood drop to have a circular or slightly elongated shape; this helps in the determination of the angle of impact (Swgstain 2009 ). Sometimes, a trail can be formed due to the dripping of blood from a weapon as well as in case of blunt or trauma injuries, due to which large volume of blood can be encountered at the crime scene (James et al. 2005 ; Peschel et al. 2011 ).

Spatter patterns

These are patterns formed when hard objects are used to strike the victim (example: a pipe). Forward spatter on the other hand is a pattern formed towards the direction of damage (example: bullet creating an exit wound) (James et al. 2005 ; Peschel et al. 2011 ). Back spatter is a pattern formed by blood when damage is to a hard surface like the skull by a bullet, and the bloodstains will be pointing away from the impact. Gunfire spatter can also vary on the caliber of the weapon used, location of impact, and the location of the victim (James et al. 2005 ; Peschel et al. 2011 ).

Projected patterns are irregular patterns that are due to the motion of weapon (example: stabbing). If in case at the crime scene there was existence of droplets of blood of varied sizes, it is called a cast-off pattern (example: injuries by hammers) (James et al. 2005 ). In case of injury to the artery, the blood from the blood vessel flows like a fountain (upward to downward flow), a zig-zag pattern will be observed until the pressure of the lungs reduces. If there was injury internally, expiration from the mouth/nose releases blood that creates a pattern very small to see (fine mist-like) (James et al. 2005 ; Peschel et al. 2011 ).

Altered patterns

Bloodstain patterns that indicate that a physical change had occurred can be said as altered patterns. This change can be due to physical activity, diffusion, dilution, or insects’, which can misguide the investigators to consider them as drip patterns. In case if the body was dragged over pre-existing blood, it leaves a tangential path (James et al. 2005 ). Contact prints may also be recovered on clean surfaces at the crime scenes (bloody shoe prints, fingerprints, or the entire palm) that can help investigators in determining what might have occurred at the crime scene. This can help investigators to determine what object could have been at the crime scene (James et al. 2005 ; Peschel et al. 2011 ).

Void patterns on the other hands are formed when an object is placed between the blood source and projection area, it is likely to receive some of the stains, which consequently leads to an absence of the stains in an otherwise continuous bloodstain pattern, which can indicate that an object or person would have been a part of the pattern (like a missing object from the wall) that if recovered can help in completing the pattern (James et al. 2005 ; Peschel et al. 2011 ).

Insects that move over the blood can also create a unique pattern that can often confuse the investigators to what pattern it could be. When blood comes into contact with clothing and fabric it spreads via diffusion, often leaving an irregularly shaped pattern which is difficult to interpret, especially in that cases the surface could be collected and send for examination to forensic labs (James et al. 2005 ; Peschel et al. 2011 ).

Moreover, to reconstruct the events that caused bloodshed, the investigators use the direction and angle of the spatter to calculate the areas of convergence (it is the starting point of the bloodshed) and area of origin (point from where the blood immerged) to mark the location of the victim and perpetrator (James et al. 2005 ) (Fig. 1 ).

Fake blood stains that were made using Awlata dye

Different works have been carried in blood pattern analysis, a study showed that when determining area of origin from blood stains, larger drops which are elliptical should be given more consideration (de Bruin et al. 2011 ). In another study, the velocities of blood were considered with factors like air drag and gravity which was used to predict the back-spatter formation by carrying the experiment using a blood-soaked sponge (Comiskey et al. 2016 ).

Fluid dynamics was also given consideration in blood pattern analysis to understand how the blood behaves as a liquid when in air and the factors that are affecting the formation the blood drop (Attinger et al. 2013 ). Study of spines and satellite on basis of velocity has also depicted the formation of bloodstains (Attinger et al. 2013 ).

In a real-time setting, studying bloodstains and its patterns using real blood can be a tedious task, as it requires a large amount of blood. Moreover, in order to carry out such a study, it will require ethical clearance as well as financial support. Using Awlata dye for studying bloodstains can solve these problems because of its easy availability, low cost, and it can be made under laboratory conditions. Thus, investigators and scientists can use this for experimental purposes and to carry future studies.

Article selection criteria for review

The initial criteria for selecting literature were based on searching different keywords on Google searching engine for blood, blood pattern analysis, and blood pattern analysis in forensic science. Then, after screening of articles based on the title and abstract of papers, papers were sorted. Articles and relevant internet sources that matched the relevant criteria of the review were also selected.

Article eligibility criteria for review

Eligibility of articles was finalized by analyzing whether the papers were discussing about BPA and its related methodology or not.

On basis of analyzing existing literature, it was decided that a study needs to be conducted by creating fake bloodstains using Awlata, so as to understand the formation of stains if the angle is kept fixed and the height is varied (Buck et al. 2011 ; Attinger et al. 2013 ). An Indian dye (Awlata/Alta) was used to make fake blood stains to depict similar patterns as that of blood. Awlata (Alta) is a traditional Indian red dye used by women in the festive season and is applied to hands and feet. For the experiment Awlata dye, a Pasteur pipette and white chart papers were used. The experiment was carried within the university premises in the university laboratory.

Preparation/composition of Awlata

In cultural practices, Awlata dye was made from Betel leaves which is a vine from the family Piperaceae. Awlata is also made from the extract of lac that is a red dye obtained from the scale of an insect Laccifer Lacca. Nowadays, Awlata can be made chemically by using Vermillion (red powder) with water to make a liquid.

Source of Awlata for the experiment

For this experiment, a ready-made Awlata dye (Pari) was bought from the local market which had its composition defined and came packed in a 50-ml bottle. The reason for taking Awlata for experiment, was Awlata dries within a few minutes and its life span is about 1–2 months, after which it starts to fade. But if it is preserved and stored properly, it can stay intact for long durations.

Formation of fake bloodstains

In this experiment, we conducted different height variations to create fake bloodstains using Awlata dye (Buck et al. 2011 ; Attinger et al. 2013 ). The experiment aimed to study the shape (morphology) of these fake bloodstains at different heights (3, 4, 5, 6, and 7 feet) so that an approximate estimation of actual blood stain formation can be studied (Attinger et al. 2013 ). A Pasteur pipette was used for this experiment and about 0.5 ml of Awlata dye was taken for making a single fake blood stain.

The amount of Awlata dye that was used to make a single fake blood stain was ascertained using the indications labeled on the Pasteur pipette. Ninety-degree angle was maintained and the Awlata dye was dropped from different heights and observations were made. For each height, two stains were made and labeled drop 1 and drop 2; this was done to compare the observation and confirm the findings.

After Awlata dye was dropped from different heights to create fake blood stains, it was observed that as the height was increased, the distance of satellite stains emerging from the fake blood stains was also increasing. It can be observed that fake blood stain created from three feet has many numbers of spines and less satellite stains and they are very close to the parent stain. Similarly, as the height was increased, the numbers of spines were reduced and the number of satellite stains was increased.

The experimental observation noted was that as the height was increased, the force of gravity acting on the Awlata dye was also increasing, and hence when the Awlata dye was dropped from a height to create fake blood stains, the impact of the dye on the surface due to gravitational forces, inertial forces, and viscous forces (Attinger et al. 2013 ) could be the possible cause of formation of such stains. To ascertain the formation of these fake blood stains, we retook the height experiment and the observations were very similar to that of the first drop (see Table 1 ).

Discussions

After the experiment carried with Awlata dye, it was observed that height was directly proportional to the number of satellite stains (stains that are small droplets moving away from the parent stain, they are partially/not attached to the parent stain), i.e., more distant the satellite stains from the parent drop, more will be the height. Whereas relation of spines (these are small projections coming out from the parent stain, they remain attached to the parent stain) and height was inverse in nature, i.e., when the height was increased the number of spines reduced.

Though Awlata was used to study the formation of fake blood stains, care must be taken that this dye should be kept away from contact with moisture/water as repeated moisture/water tends to fade the dye and also wash it off. So, if Awlata dye is used for future studies, the observations made from this dye should be properly stored and preserved. This will help ensure the integrity of experimental findings is not altered.

Factors like size, age, and health of the individual should also be given consideration while studying the blood stain formation. Moreover, surface tension also plays an important role in the formation of bloodstains (Larkin et al. 2012 ). Surface tension is also varied if there is some chemical or other chemical present in the blood (Raymond et al. 1996 ). The surface roughness, permeability, and porosity also effect the formation of bloodstain formation. So, these factors are also needed to be given consideration when studying bloodstains (Bear 1975 ).

Study of fake bloodstains using Awlata dye highlights these potential aspects and on basis of existing literary works carried by other scientists a more definite version of BPA can be worked upon. Study of fluid dynamics should also be given consideration while studying bloodstain formation (Attinger et al. 2013 ). To open new gateways of research in BPA and support investigative observations, the findings depicted in this paper can be used as a source to validate actual blood stains and also carry out future studies. Domains like how angle variation with respect to height effects formation of blood stains can be explored on the basis of these findings. This finding can help to understand the formation of blood stains for future research and development.

The future of BPA is promising and more research needs to be done to improve BPA. A more precise method of blood interpretations should be created to make investigations more accurate, so that crime scene reconstruction can be carried out efficiently. The study conducted using Awlata dye can be a contributor to the existing literature on BPA. This paper is a review work which can be utilized by students, scientists, or experts as a reference for carrying out future studies or to enhance their knowledge. Blood pattern analysis is indeed a useful tool in forensic science which can help in crime scene reconstruction and if BPA is coupled with DNA analysis and other investigative findings, more conclusive and thorough details of the sequence of events can be obtained from blood evidence.

Limitations of Awlata dye

The composition of Awlata dye (Alta) and blood vary; hence, Awlata dye (Alta) cannot be considered as blood. Awlata was used to create fake bloodstains which can give an approximate idea towards BPA and resemblance somewhat similar to actual blood stains. The actual scenario at the crime scene that led to the formation of blood stains and that made by Awlata dye has scope for human errors too as studying blood stains in real and that in experimental conditions differ.

Awlata dye use in the forensic scenario

Studying BPA is a very skillful task, and at the crime scene when real blood is concerned, the scenarios are simultaneous and unpredictable. To carry studies to understand bloodstains is not always possible; it requires a large amount of blood which is subjected to ethical clearance. Awlata dye can be an emerging substitute to this problem, as it is cost-effective, readily available, and can also be made in the lab. Awlata dye can be used to create experimental conditions to study different forensic scenarios. Fake blood created with Awlata dyes can be used to make simulated crime scenes from forensic and investigative findings to derive case supportive conclusions.

From the experiment done using Awlata dye ( Alta ), it can be concluded that blood stains can help experts estimate the approximate height of the assailant. The formation of the bloodstain can correspond to the height it originated from, thus being a vital source of information. A relation of formation of blood stains with change in varying height was established in accordance with interpretation of spines and satellite stains. Though Awlata is not similar to blood, it can be used to carry out experimental studies to explore more about BPA. Existing studies on BPA depict that blood patterns are very useful source of information and it can help investigators to examine the crime scene precisely.

Availability of data and materials

Not applicable

Abbreviations

Blood pattern analysis

Deoxyribonucleic acid

Ultra violet

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School of Forensic Science, National Forensic Sciences University, Gandhinagar, Gujarat, India

Prashant Singh & Nandini Gupta

Department of Chemistry, Biochemistry and Forensic Sciences, Amity University, Manesar, Haryana, India

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PS and NG worked on researching relevant data and writing of this review paper. RR was our guide and mentor who constantly guided us and helped formulate the different sections of the review and did the final check. We clarify that all authors have read and approved the final manuscript.

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Singh, P., Gupta, N. & Rathi, R. Blood pattern analysis—a review and new findings. Egypt J Forensic Sci 11 , 9 (2021). https://doi.org/10.1186/s41935-021-00224-8

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Bloodstains

Bloodstain Pattern Analysis: The Case of David Camm

By: Bill Clutter

The first use of blood stain analysis in an American courtroom occurred in 1966, in the re-trial of Sam Sheppard, an Ohio physician who spent over 10 years in prison before being freed. Sheppard had been convicted in 1954 of bludgeoning his wife to death in her bed, but maintained his innocence, claiming the attack was perpetrated by an intruder. This famous case inspired the TV series The Fugitive (1963-67) and the 1993 movie, starring Harrison Ford. The U.S. Supreme Court vacated the original conviction because of pre-trial publicity that made it impossible to receive a fair trial. F. Lee Bailey, gained fame as a criminal defense lawyer by winning an acquittal on re-trial. Dr. Paul Kirk, a criminologist at the University of California, Berkley, conducted a reconstruction of the crime scene and provided the first expert testimony interpreting for the jury patterns of cast-off and impact spatter bloodstains that were present at the crime scene. His testimony helped win Sheppard’s freedom. However, it was Herbert L. MacDonell, who is credited with establishing the profession of Bloodstain Pattern Analysis (BPA). In 1971, MacDonell wrote Flight Characteristics and Stain Patterns of Human Blood , the first authoritative BPA training manual. In 1983, he organized a meeting of his disciples whom he trained in Corning, NY and organized the International Association of Bloodstain Pattern Analysts (IABPA). To acquire a better understanding of this specialty, I attended a bloodstain pattern analysis course sponsored by Bevel Gardner & Associates.

THE CAMM CASE: “A BLACK-EYE” TO THE BPA PROFESSION After giving an overview of BPA history, the instructor mentioned that the bloodstain profession has taken a few hits with the 2009 report from the National Academy of Sciences that was critical of some of the practices of BPA in American courtrooms. He noted that one case in particular, the David Camm case in Indiana, has given the profession “a black eye”. I had watched the CBS 48 Hours story on the Camm case several years earlier, so I was aware that former Indiana State Trooper, David Camm’s alibi had been corroborated by eleven men. He had been playing basketball at a church where his uncle was the pastor. The game started around 7 p.m., about the same time that his wife and two children were last seen alive. The men played basketball for about two hours and David was there the entire time, according to those who played ball with him. At approximately 9:26 p.m. he arrived home and called his old post at the Indiana State Police after finding the bodies of his wife and two children in the garage of their home in Georgetown, Indiana.

David told police he found his wife lying on the floor of the garage. She had a single bullet wound to the head. He found his five-year-old daughter, Jill, in her seat belt in the back seat of his wife’s Ford Bronco inside the garage. Jill had been shot once in the head. His son Brad was slumped over the back seat as if he had attempted to escape to the back cargo area when he was shot. David said his son’s body felt warm, possibly still alive. David climbed into the back seat, carried his son out of the vehicle and laid him next to his mother so he could perform CPR. Brad died from the single gun-shot wound that entered just under his arm pit. At autopsy, the pathologist found possible evidence of a possible “sexual assault” in Jill’s vaginal area which immediately changed the dynamics of the homicide investigation. The demeanor of the questioning toward David became accusatory. However, a week earlier, the child’s pediatrician had noticed the same inflammation, but attributed it to aggressive wiping or possibly a reaction to bubble baths. A mandatory reporter, the family doctor was not alarmed. No report of child abuse had been made at that time.

Prosecutors decided to call in a bloodstain pattern “expert” who had a reputation for assisting in the prosecution of cases that were difficult to prove. Two days later, David Camm was arrested for first degree murder, based on an interpretation of eight tiny bloodstains on his t-shirt. The “expert” who had been called to the crime scene interpreted these stains as high velocity impact spatter from allegedly firing the gun that killed his family. Some of the leading experts in BPA, however, disagreed, and said the stains were caused by transfer from coming into contact with his 5 year-old daughter’s hair that was saturated with her blood when he removed his son from the vehicle.

Robert Stites was the so-called “expert” in crime scene reconstruction and bloodstain pattern analysis who arrived in New Albany, Indiana to assist Floyd County prosecutor Stan Faith. Stites, however, was merely a crime scene photographer who was working at the direction of Rodney Englert. The real “expert” was Englert, who was a Charter Member of the International Association of Bloodstain Pattern Analysts (IABPA). Englert was not able to travel to the crime scene, so he sent his photographer. Police were unaware at the time that Stites was unqualified to render opinions about blood-stain analysis, but he did. Prior to traveling to Indiana, Stites had never taken any courses on bloodstain analysis or crime scene reconstruction, and was not a member of any blood stain analysis organization. The Indiana State Police evidence technician, who was initially in charge of processing the crime scene, had strong reservations about the so-called “expertise” of Robert Stites. After watching Stites the seasoned CSI realized that Stites didn’t know what he was doing.

The CSI came to this realization after Stites claimed there was evidence of clean-up at the crime scene. He said there had been a clear watery substance added to the large volume of blood that flowed downward to the edge of the garage away from the wife’s head wound. It turns out that it was serum separation, which helped provide a timeline as to when the murders happened. A defense bloodstain expert calculated that it would have taken about two hours for the serum to separate, placing the time of death at around 7:30 p.m. Stites arrived at the crime scene on Sept. 30, 2000. On the following day, David was arrested based on Stite’s opinion that high velocity impact spatter was present on David’s gray t-shirt known as Area 30. The police officer who served the arrest warrant, had reservations about arresting David based on the opinions of Stites. The affidavit that prosecutors drafted that provided probable cause to arrest Camm relied entirely on the opinions of Stites. Stites observed eight small blood stains on the front left side of David’s t-shirt that were less than one millimeter in diameter. The size of stains, he said, meant this had to have been high velocity impact spatter from being in close proximity to a fired gun. Backspatter and forward spatter from a bullet penetrating a blood source at high velocity can project a fine mist pattern of blood stains; backward as the bullet penetrates the object and forward as the bullet exits. Blood stains from high velocity impact spatter typically are less than a millimeter in diameter, as is found on David’s t-shirt. However, as I learned from my BPA training, “Both expectorate blood [aspirated from the mouth] and flies produce patterns that an analyst can misidentify as impact spatter”, according to Tom Bevel’s book Bloodstain Pattern Analysis: with an Introduction to Crime Scene Analysis. Bevel cautions that it is, therefore, important for the analyst to consider the full context of the crime scene.

EXPERTS FOR THE DEFENSE Blood stain experts Bart Epstein, Terry Laber, Stuart James, and Paul Kish, some of the most respected bloodstain experts in the country testified for the defense. They expressed their professional opinions that the small spots of blood on David’s t-shirt were transfer stains caused by the t-shirt coming into contact with blood saturated strands of his daughter’s hair. However, none of the State’s bloodstain experts reported observing high velocity impact spatter stains on David’s shorts. The absence of spatter stains on David’s pants adds strength to the conclusion that the stains on Area 30 were caused by transfer from the shirt coming into contact with his daughter’s blood soaked strands of hair. The linear pattern of the stains is also not consistent with high velocity impact spatter. One would expect to see a conical pattern of dispersal from high velocity impact spatter (both forward and back spatter) when a bullet fired from a gun impacts a body of blood. However, the bloodstains on Area 30 form a straight line, a pattern that is more consistent with a transfer of blood from strands of hair from a head wound.

MISUSE OF BPA IN AMERICAN COURTROOMS My first case involving Rodney Englert, was a Lawrenceville, IL woman who was facing the death penalty. In June of 2000, I received a phone call from Katharine Liell, a criminal defense attorney from Bloomington, IN. Ironically; she would later represent David Camm. Her client, Julie Rea, was a Ph. D. student at Indiana University. It was a cold-case. Three years had gone by since the murder of Julie’s son, 10 year-old Joel Kirkpatrick. On Oct. 13, 1997, at 4 a.m., Julie was awakened by her son’s screams for help. When she went into his room, she startled an intruder. He had just stabbed her son to death with a knife that came from her kitchen. The elected state’s attorney resisted pressure from the sheriff and her ex-husband to place her under arrest. The prosecutor made a public statement that there was not enough evidence to arrest anyone. After he left office, a special prosecutor intent on charging Julie Rea with a capital offense was appointed to take charge of the investigation. The special prosecutor hired Rodney Englert.

Englert was able to see evidence of cast off bloodstains in his interpretation of the night-shirt Julie was wearing when she encountered the intruder. Englert opined that the cast-off stains were allegedly caused when the mother drew back the knife after repeatedly stabbing her son to death. Bloodstain interpretations previously made by forensic scientists from the Illinois State Police could only find transfer patterns consistent with the mother’s story about colliding into an intruder and struggling with the man. She had a black eye where the man had punched her in the face, and she had a gash on her arm that required sutures. I told Julie’s attorney that if I was appointed to her client’s case, I would want to investigate whether Tommy Lynn Sells had been in the area at the time of the murder. A child serial killer, Sells had just been arrested in Del Rio, TX, for a similar crime in which he broke into a trailer at 4 a.m and used a knife from the kitchen to kill Kaylene Harris while her mother slept. However, prosecutors decided not to seek the death penalty in a maneuver to avoid reforms that would have leveled the playing field by providing Julie’s defense with financial resources to investigate her innocence prior to trial. After Julie was convicted in March of 2002, Diane Fanning published Through the Window: The Terrifying True Story of Cross-Country Killer Tommy Lynn Sells. Sells had told Fanning about a murder in Illinois in which he had killed a child and was startled by the mother who came into the room. He said he would have killed her too, if he hadn’t dropped the knife. Crime scene investigators found the bloody knife on the floor at the doorway, where Julie said she encountered the man.

I was able to corroborate the confession with witnesses who reported to their sheriff an intruder who matched Sell’s physical description. Based on this evidence, Texas Ranger John Allen provided an affidavit supporting Julie’s petition seeking to overturn her conviction. However, after her conviction was overturned the same prosecutors and police investigators who got it wrong dug in their heels and decided to disbelieve the confession before consulting with Texas law enforcement authorities. They re-arrested Julie just as she was about to be released from prison and set her case for re-trial. A new jury, hearing the evidence of the serial killer’s confession found her not guilty in 2006. She was represented by the Center on Wrongful Convictions at Northwestern University Law School pro bono. She subsequently received a Certificate of Innocence.

On June 2, 2003, a year after Englert’s testimony was used to persuade juries to convict David Camm and Julie Rea, an ethics complaint against Englert was filed with the American Academy of Forensic Science by some of the most respected bloodstain experts in the country alleging that Englert had misrepresented his education, training and experience. Subsequent to this, Englert filed suit against Herb MacDonell (regarded as the father of the BPA profession) alleging slander for calling Englert among other things “a forensic whore”, “liar-for-hire”, “a very smooth charlatan”, and “the Bin Laden of bloodstains”. In 2009, the National Academy of Sciences released a critique of forensic science practices in U.S. courtrooms, noting that since the introduction of DNA testing in 1989 that “faulty science” was found to be responsible for the wrongful convictions of a number of post-conviction DNA exonerations. BPA was one of several disciplines that were faulted because of the interjection of “examiner bias” that may lead to erroneous conclusions when interpreting evidence like bite marks, tool marks and bloodstains. The report noted “many sources of variability arise with the production of bloodstain patterns, and their interpretation is not nearly as straightforward as the process implies”. The report found, “some experts extrapolate far beyond what can be supported”, and went on to conclude that “extra care must be given to the way in which the analyses are presented in court. The uncertainties associated with bloodstain pattern analysis are enormous”.

DNA IDENTIFIES CHARLES BONEY Four years after David Camm was arrested, his conviction was reversed in Aug. 2004, because prosecutors had unfairly inflamed the jury by introducing testimony about his extramarital affairs. Some of his affairs were with women with whom he worked at the Indiana State Police Sellersburg Post, which had taken charge of the homicide investigation. A new team of investigators were called into the case to be “fresh eyes”. They discovered from their review of the file that there had been a grey sweatshirt that was foreign to the crime scene. The sweatshirt was found underneath Brad Camm’s body, where his father laid his son next to his wife. The inside collar had the moniker “BACK-BONE” written in black ink. At the very beginning of the investigation the collar had been swabbed by a forensic scientist to identify the wearer’s DNA. An unknown male DNA profile was identified. Prior to David’s first trial his defense attorney asked the prosecutor, Stan Faith, (who had charged David) whether this DNA profile had been entered into CODIS, the FBI offender DNA database. The prosecutor told the defense attorney that it was submitted, but there was no hit. This was a false representation, which obstructed justice for David Camm.

Years later, after an appellate court reversed David’s conviction, Camm’s new attorney, Katherine Liell, requested that the DNA be entered into CODIS. In Feb. 2005, a CODIS hit came back identifying a career criminal named Charles Darnell Boney whose prison nickname was BACK-BONE. He had been released from prison a few months before the Camm family was killed. Known as the “Shoe Bandit”, Boney had a foot fetish and was sexually aroused by holding women at gunpoint and stealing their shoes. One of the female troopers who arrived at the crime scene had noted in her report that it was odd that the shoes of David’s wife had been removed from her feet and were placed on top of the vehicle.

Now, it all made sense. Although his wife’s shoes and pants had been removed, there was no evidence of a sexual assault in the conventional sense. So investigators dismissed the idea that the crime was motivated by the behavior of a sexual predator. But knowing Boney’s sexual predilection of being aroused by women’s bare feet and legs, the artifacts of the crime scene fit perfectly with his MO.

THE PROSECUTION COMPLEX Chicago Sun Times reporter Tom Frisbie described the “Prosecution Complex” in his book Victims of Justice , about the infamous Nicarico case. Instead of seeking justice when new and exonerating evidence was found proving the innocence of Rolando Cruz, which included DNA and confession of a serial killer, the police and prosecutors who got it wrong tend to circle the wagons to fend off the attack on the original conviction. In that case, police and prosecutors were eventually indicted for a conspiracy to obstruct justice. Less than a month after DNA identified Charles Boney, his palm print was found on the door frame of the passenger side of David’s wife’s Ford Bronco. This palm print is consistent with Boney having reached inside the vehicle to fire the shots that killed 7 year-old Brad, and his 5 year-old sister, Jill, who was still seat belted inside the vehicle. Earlier, a judge had lowered David’s bond. He was released to what remained of his family. His uncle, Sam Lockhart, who had been playing basketball that night with David, bonded him out of jail. But now Boney was given a choice. He could be charged with the death penalty, or he could cooperate and assist prosecutors with their theory that Boney provided the gun to David Camm that he allegedly used to kill his family. Boney initially denied knowing David when he was interviewed in February. A month later, with this new and compelling evidence of his palm print, Boney’s life depended on which choice he made. Despite his previous series of proven lies, Boney changed his story, and now said he met David playing basketball and after this first meeting arranged to sell him a gun that he wrapped in his sweatshirt. However, this does not explain why David’s wife’s DNA is on the left sleeve of the sweatshirt. The autopsy revealed that David’s wife had struggled with the assailant and had injuries suggesting she had been choked.

Nevertheless, David was re-indicted for conspiracy to commit murder and has been confined to a prison cell ever since. Although Boney was convicted of conspiracy to commit murder and remains in prison, he recently said he has every expectation of being a free man someday. EXONERATING THE INNOCENT The highlight of my BPA training was the arrival of Tom Bevel. He had been on the road most of that week testifying in court. During the noon break after his presentation, he told me about his work on a case in North Carolina where he had provided testimony of his interpretation of bloodstain evidence that had helped to exonerate an innocent man On Feb. 10, 2010, he provided testimony for the North Carolina Innocence Project before an independent panel of three judges. This special commission was created by the state’s Supreme Court to establish an independent review of inmate claims of actual innocence called North Carolina Innocence Inquiry Commission, the first of its kind in the nation. Bevel’s testimony persuaded the three judges that there was clear and convincing evidence demonstrating the innocence of Greg Taylor. Taylor was granted a full pardon on May 21, 2010, and was released from prison. He had been wrongfully convicted in 1993 of first degree murder based on erroneous testimony concerning bloodstain evidence. He spent nearly two decades in prison for a crime he did not commit.

A few years before that, Bevel had also assisted with the release of Tim Masters, an innocent man who had been convicted of murder in Colorado. In that case, Bevel reversed the previous opinion he had given that originally helped to convict Masters, after he had been provided additional evidence that had been concealed from him by the police detective who was later indicted for his alleged misconduct in the case.

Some of the real heroes in cases like this are guys like Tom Bevel, who dare to reveal their humanity by admitting when they get it wrong, but are willing to work to make it right.

( On October 24, 2013, David Camm, walked free after 13-years in prison after a jury in Lebanon, Indiana found him not guilty in a third re-trial. His case was the first exoneration for Investigating Innocence , which was started earlier that year. Bill Clutter, who started the project, was a member of Camm’s defense team and suggested conducting an animated crime scene reconstruction, which helped persuade the jury that David Camm is innocent. Students at the University of Indiana assisted Clutter and the Camm defense team in reviewing the case and provided a fresh set of eyes. ( Read more about the exoneration here. ) Bill Clutter is a board certified member of the Criminal Defense Investigation Training Council. He started the Illinois Innocence Project in 2001, and is the Director of Investigations for a national innocence project called Investigating Innocence that he started in January 2013.

How Bloodstain Pattern Analysis Works

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Bloodstain Pattern Analysis in Action: The Chamberlain Case

One infamous case that comes to the minds of many people when thinking about blood spatter analysis involves a line that has since become a pop culture catchphrase, thanks to Meryl Streep in "A Cry in the Dark" and Julia Louis-Dreyfus on "Seinfeld": " The dingo ate my baby. "

In August 1980, the Chamberlain family camped near Uluru (formerly known as Ayers Rock) in the Red Centre desert of Australia's Northern Territory. One night, Lindy Chamberlain put two of her children, 4-year-old Reagan and 9-week-old Azaria, to bed in their tent. When she returned, the story goes, she cried, "The dingo's got my baby!" [source: Latson ].

According to Lindy , when she got to the tent she saw a dingo with a bundle in its mouth. She wasn't close enough to see what it was, but when she checked on the children she saw that her daughter Azaria was missing [source: Haberman ]. As the cry went out, she and her husband, Michael, along with other campers, began searching for the child. A nearby camper, Sally Lowe, went into the tent to check on the still-sleeping Reagan. Seeing a pool of wet blood on the floor of the tent, she thought that Azaria was probably already dead [source: Linder ].

When a tourist found the baby's jumpsuit, it was only slightly torn and bloody, but mostly intact. Though an initial investigation backed up Lindy's claim of a wild dog attacking her daughter, it was not long before the parents themselves stood accused [source: Haberman ].

The baby had been wearing other clothes that weren't found at the time.

Throughout the case, the local police improperly handled blood spatter and other evidence. Forensics investigators found "blood stains" in the family car and concluded that Lindy had taken Azaria there to cut her throat. Later analysis revealed that the stains came from a spilled drink and a sound-deadening compound that came with the car. One expert identified a "bloody handprint" on Azaria's jumpsuit that later analysis revealed to be red desert sand.

However, in 1982, expert testimony — and public opinion — proved enough to convict Lindy Chamberlain of murder and her husband of being an accessory to murder. The baby's knit jacket, found four years later in 1986 near a dingo lair, helped exonerate the Chamberlains after Lindy had served three years of a life sentence, but several years of trials and hearings were yet to come [source: Latson ]. In 2012, 32 years after the event, a coroner finally pronounced that a dingo was responsible for Azaria's death [sources: Haberman , Latson ].

The Chamberlain case shows what can happen when people involved in handling and analyzing blood evidence lack proper training, or when investigators allow public opinion or preconceived notions to influence their analysis.

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How blood pattern analysis can be used to solve a murder: the Gareth MacDonald case

News December 01, 2021

By Forensic Access

Forensic Access recently featured in the BBC’s new true crime series which explored the role of scientists in forensic investigations, showing how some of the UK’s most serious crimes were solved. Episode 14: Paint Materials and Blood Patterns covered Forensic Access’ resident BPA expert, Dr. Philip Avenell’s, involvement with the Gareth MacDonald case. Here we tell the story of how Blood Pattern Analysis was used to solve the murder and bring Mr. MacDonald’s killer to justice.

The body of Gareth MacDonald, 30, was discovered in a Travelodge hotel room after he sustained multiple blows to the head in September 2007.

He was found in a ground floor room at Heston services next to the M4 motorway early on the morning of Saturday 15 th September. There was a significant amount of blood on the bedsheets and it appeared at an early stage that a fire extinguisher discovered at the scene was the murder weapon.

MacDonald, a father of three from Prestatyn, North Wales was headed to London with his boyfriend Glenn Rycroft, who he met online the year before. Rycroft claimed that MacDonald was safe and well when he left the hotel room at 07:00 that morning, but when he returned fifteen minutes later, he discovered MacDonald lifeless in a pool of blood.

However, there were no signs of forced entry, and Rycroft was stained with the victim’s blood with his fingerprints were discovered on the murder weapon. His explanation for this was that he attempted to hug Gareth’s body, which meant that he himself became covered in the deceased’s blood.

Rycroft’s actions had contaminated the crime scene, meaning that finding forensic evidence was now a major challenge. This is when the police turned to forensic science for help, enlisting the expertise of Dr. Philip Avenell who is a specialist in blood pattern analysis.

The police first submitted the shoes that Rycroft has been wearing at the time of his arrest. The right shoe had some blood staining on it but there was nothing particularly distinctive there, whereas the left shoe had a very clear impact spatter on it.

“The front on view the shoe showed a distribution of blood spatters across it of varying sizes – but many of them very small.

“Small blood stains won’t travel very far, so you can start to get an idea of how far away the perpetrator was. The shoe was close to impact with wet blood,” Dr. Avenell said.

Due to the colour and texture of the material that some items are made out of, it is not always easy to clearly see blood on an exhibit, particularly the fine detail. Because of this, scientists will make sketches or use software to represent basic images of an item, which can then be annotated to clearly show exactly where the blood appeared and the type of blood staining present.

“From the digital sketch you can see there is a lot more blood on there than is visible to the naked eye when you are looking at the exhibit. It really highlights that there was a heavy impact from wet blood that’s made its way onto the shoe,” Dr. Avenell said.

Rycroft claimed to have found MacDonald deceased when he went back to the hotel room, however the blood pattern evidence on Rycroft’s shoes told a different story. It showed that Rycroft could have been in the room when MacDonald was fatally injured. The police now had crucial evidence that potentially placed Rycroft at the scene of the crime.

The prosecution now required further proof of what had happened in the hotel room. Blood spatter on Rycroft’s shoes showed that he was in close proximity to MacDonald when there had been a heavy impact into wet blood, and further examination of Rycroft’s clothing was needed.

Dr. Avenell examined the trousers that Rycroft had been wearing at the time of MacDonald’s murder and had been recovered from Rycroft when he was taken into police custody.

“There was a lot of heavy blood staining on the trousers. This is what we call contact blood staining, where the item has leant into something that’s wet with blood or vice versa.

“There’s difficulties when you have lots of heavy blood stains and lots of different types of blood patterns overlaying each other. It then becomes quite difficult to work out exactly what’s there. That’s when you’re looking at the very fine, small detail in the blood,” he said.

Dr Avenell began an intricate examination of the blood stains on Rycroft’s trousers, finding a small yet vital clue. Around halfway up the left leg, the team found three very small blood stains which were identified as blood that’s travelled through the air and landed on the surface of the trousers.

The consistency of the blood was clearly different to that of the other blood stains, proving to be clotted blood which meant that these blood stains were made at a different time.

Dr. Avenell then turned his attention to the bedsheets. They were also soaked in blood, but amongst the heavy staining he discovered further evidence of clotted blood – just like on Rycroft’s trousers.

“We could see where the impact had happened and the blood radiated out from the point of impact. From the initial impact, the blood started to flow and then there was a time delay for that blood to start clotting. This showed there had been a second impact into the blood after that,” he said.

For Dr. Avenell, this information provided a sequence of events surrounding MacDonald’s murder. It showed that MacDonald had been struck once, then a minimum minutes later as the blood was beginning to clot, he was struck a second time.

“We knew there had been an impact into blood after there had been a period of time of bleeding. Typically, this is between three and fifteen minutes. It showed there had been at least two blows and that the blows were minutes apart.

“You look at what you’ve got and you try to understand the timeline of events and what has happened. It’s interesting when you then start to piece them together,” he said.

Blood pattern analysis by Dr. Avenell was pertinent to the prosecution’s case, providing police with the definitive answer which DNA evidence and fingerprints evidence would not have achieved.

In July 2009 Glenn Rycroft stood trial at the Old Bailey. He was found guilty of murder and sentenced to life in prison, serving a minimum of twenty-five years.

Blood Pattern Analysis Expertise

The world-class team of forensic scientists at Forensic Access operate in bespoke facilities. The forensic work we carry out is to the highest quality standards.

We have a dedicated team of Casework Managers who support all defence work, providing end-to-end assistance and coordination. The Casework team has direct access to our team of scientists, helping barristers and solicitors prepare a more effective defence strategy, and all expert witness reports are thoroughly documented and peer reviewed.

To learn more about the forensic services we offer, or to receive a free consultation and quote, please fill-in our contact form or Tel: 01235 774870.

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The New York Times

Magazine | how an unproven forensic science became a courtroom staple, how an unproven forensic science became a courtroom staple.

By LEORA SMITH and PROPUBLICA MAY 31, 2018

A timeline of a niche, unproven discipline that gained a hold in the American justice system.

By LEORA SMITH, PROPUBLICA MAY 31, 2018

Testimony from bloodstain-pattern analysts is now accepted in courts throughout the country. But in recent years, some scientists and legal scholars have questioned the training of these experts, as well as the validity of the field itself. How did a niche, unproven discipline gain a hold in the American justice system and proliferate state by state?

The modern era of bloodstain-pattern analysis began when a small group of scientists and forensic investigators started testifying in cases, as experts in a new technique. Some of them went on to train hundreds of police officers, investigators and crime-lab technicians — many of whom began to testify as well. When defendants appealed the legitimacy of the experts’ testimony, the cases made their way to state appeals courts. Once one court ruled such testimony admissible, other states’ courts followed suit, often citing their predecessors’ decisions. When discussing the reliability or accuracy of the technique, judges typically relied on their own — or the testifying expert’s own — assessment. Rarely, if ever, have courts required objective proof of bloodstain-pattern analysis’ accuracy.

Sam Sheppard, an Ohio doctor, is convicted of murdering his wife in a case that attracts widespread attention. Paul Leland Kirk, a renowned scientist and criminalist who worked on the Manhattan Project, studies the bloodstains in the Sheppard home and, the following year, offers an interpretation of events that the defense believes exonerates Sheppard.

People v. Carter

The Supreme Court of California affirms that bloodstain-pattern analysis is a proper area for expert testimony and that Kirk is a qualified expert in the field. The case is possibly the earliest instance of an appellate court explicitly accepting bloodstain-pattern analysis as an appropriate field of expertise.

• Sets precedent in California.

Sam Sheppard is retried, and Kirk’s findings play a central role in Sheppard’s defense. Sheppard is found not guilty.

Pedersen v. State

The Supreme Court of Alaska holds that bloodstain-pattern analysis is an acceptable area for expert testimony. An Alaska State Police officer uses blood spatters on a crab-fishing ship to determine where the victim was standing when shot.

• Sets precedent in Alaska.

The United States Department of Justice publishes a report, “Flight Characteristics and Stain Patterns of Human Blood,” by Herbert Leon MacDonell, an instructor at a two-year college in New York with a master’s degree. It becomes a foundational text in the field of bloodstain-pattern analysis.

MacDonell teaches his first Bloodstain Institute, a weeklong workshop, in Jackson, Miss., training police officers as bloodstain-pattern analysts. Months later, he teaches a second institute in Elmira, N.Y. Over the next few decades, MacDonell will train more than 1,000 new analysts.

Compton v. Commonwealth

The Supreme Court of Virginia rules that bloodstain-pattern analysis is a proper area for expert testimony. A Danville police officer testifies that bloodless circles on the floor helped determine that the victim was probably sitting at a table when shot.

• Sets precedent in Virginia.

People v. Erickson

An Illinois appellate court upholds a man’s conviction for murdering his wife. MacDonell testifies that blood patterns on the defendant’s clothes suggest that his wife’s blood spattered on him while he attacked her. On appeal, the court doesn’t rule on the issue of admissibility of experts in bloodstain-pattern analysis, because the defendant did not specifically appeal MacDonell’s admission as an expert.

• The case does not set bloodstain-pattern-analysis precedent in Illinois, but it is later cited by courts in Michigan and Texas to support the admission of experts in the field.

State v. Hall

The Supreme Court of Iowa affirms the admission of bloodstain-pattern evidence and the admission of MacDonell as an expert. The court refers to MacDonell’s field as “relatively uncomplicated” and, as a result, does not require extensive proof of its reliability. The judges write, “The evidence offered to show the reliability of the bloodstain analysis included: (1) Professor MacDonell’s considerable experience and his status as the leading expert in the field; (2) the existence of national training programs; (3) the existence of national and state organizations for experts in the field; (4) the offering of courses on the subject in several major schools; (5) use by police departments throughout the country in their day-to-day operations; (6) the holding of annual seminars; and (7) the existence of specialized publications.” The court does not acknowledge that MacDonell himself is the source of almost all these indicators of reliability.

• Sets precedent in Iowa.

State v. Hilton

The Supreme Judicial Court of Maine discusses the testimony of an expert in bloodstain-pattern analysis but does not actually rule on the issue of admissibility of such testimony.

• The case does not set precedent in Maine, but it is later cited by courts in Idaho and Texas to support the admission of experts in bloodstain-pattern analysis.

State v. Melson

The Supreme Court of Tennessee affirms a man’s murder conviction and death sentence and finds that bloodstain-pattern-analysis testimony of MacDonell was properly admitted.

• Sets precedent in Tennessee.

MacDonell holds his first Advanced Bloodstain Institute. Twenty-two graduates of the advanced class go on to form the International Association of Bloodstain Pattern Analysts, and Tom Bevel, an Oklahoma police officer and former student of MacDonell’s, becomes its first president.

Farris v. State

The Court of Criminal Appeals of Oklahoma rules that bloodstain-pattern analysis is a proper area for expert testimony. In a murder case under review, Bevel had testified that the bloodstains showed that the defendant struck the victim multiple times after shooting him and that the victim tried to defend himself.

• Sets precedent in Oklahoma, citing cases in Alaska and California.

People v. Knox

An appellate court in Illinois accepts bloodstain-pattern analysis as a proper area of expertise and holds that a police officer who takes a three-week course with MacDonell is qualified to testify as an expert.

• Sets precedent in Illinois.

Jordan v. State

The Supreme Court of Mississippi holds that even if a court erred in admitting a bloodstain-pattern analyst, the testimony was not influential enough to merit a retrial. The expert in the case attended a one-week institute with MacDonell in 1973, the first year the course was offered.

Lewis v. State

An appellate court in Texas affirms the reliability of bloodstain-pattern analysis and MacDonell’s qualification to testify as an expert witness.

• Sets precedent in Texas, citing cases in California, Illinois, Maine and Tennessee.

Fox v. State

The Supreme Court of Indiana upholds a conviction and finds that the expert in bloodstain-pattern analysis who testified in a murder case is qualified because he met Indiana’s requirements for expert witnesses: His knowledge exceeded that of an “average layperson,” and he had sufficient knowledge and skill to aid the judge and jury at trial. The detective who testified had attended one course on bloodstain-pattern analysis in 1980 and had never testified about such evidence before.

• Sets precedent in Indiana.

State v. Moore

The Supreme Court of Minnesota rules that bloodstain-pattern analysis is a proper area for expert testimony and that a serology expert who has never taken a course on bloodstain-pattern analysis is qualified enough to testify as an expert.

• Sets precedent in Minnesota, citing cases in Illinois, Iowa and Texas.

State v. Rodgers

The Supreme Court of Idaho decides that bloodstain-pattern analysis is an appropriate area for expert testimony. The two experts in the case had trained with MacDonell and Bevel. The court affirms the men’s admission as experts, saying they each meet Idaho’s legal standard, which requires only that experts be more knowledgeable on a topic than an average juror.

• Sets precedent in Idaho, citing cases in Maine, Oklahoma, Tennessee and Texas.

State v. Goode

The Supreme Court of North Carolina rules that bloodstain-pattern analysis is admissible as expert testimony and upholds the death sentence for a defendant convicted of two counts of first-degree murder. The expert, Duane Deaver, worked in forensics for the State Bureau of Investigation and had studied bloodstain-pattern analysis with former students of MacDonell and Kirk. Deaver testified that the defendant, who appeared to have no blood on his clothes, actually had minuscule blood spots on his boots.

• Sets precedent in North Carolina, citing cases in Idaho, Indiana, Iowa, Oklahoma, Tennessee and Virginia. People v. Haywood

People v. Haywood

The Michigan Court of Appeals affirms the admission of bloodstain-pattern-analysis testimony and holds, among other reasons, that because bloodstain-pattern analysis is not a novel technique, extensive proof of its reliability is not required.

• Sets precedent in Michigan, citing cases in California and Texas.

State v. Halake

The Tennessee Court of Criminal Appeals overturns a conviction of first-degree murder, finding that a police officer who had never attended a full course in bloodstain-pattern analysis was improperly admitted as an expert at trial. The court contrasts the officer’s credentials with experts admitted by other courts, including MacDonell.

Holmes v. State

The Texas Court of Appeals holds that a detective who attended one weeklong bloodstain-pattern-analysis institute is sufficiently qualified to testify as an expert witness and upholds Texas’ longstanding acceptance of bloodstain-pattern analysis as a reliable technique fit for expert testimony.

• Sets precedent in Texas, citing cases from 15 other states.

A groundbreaking National Academy of Sciences study finds serious deficiencies in the field of forensic science in the United States and notes that “the uncertainties associated with bloodstain-pattern analysis are enormous.” The authors note that “in general, the opinions of bloodstain-pattern analysts are more subjective than scientific.”

A federal court finds that Duane Deaver, who testified as a bloodstain analyst in the 1995 North Carolina case State v. Goode, had performed inadequate testing. An audit of the state forensics lab where he worked will find the next year that Deaver provided misleading information on his reports for years. By the time these findings are public, judges in Tennessee and Texas will have already have cited State v. Goode in deciding to admit bloodstain-pattern analysis as a reliable field.

In January, the Texas Forensic Science Commission holds a one-day hearing, prompted in part by its investigation into the role that a minimally trained bloodstain-pattern analyst played in the convictions of Joe Bryan. In February, the commission decides to create an accreditation requirement for bloodstain-pattern-analysis experts in Texas.

Related Coverage

Blood will tell, part 1: who killed mickey bryan.

May 23, 2018

Blood Will Tell, Part 2: Did Faulty Evidence Doom Joe Bryan?

May 31, 2018

Blood Spatter Evidence in Bryan Case

Recent testimony from an evidentiary hearing in the Joe Bryan case in Texas has centered on blood spatter interpretation. Bryan was a school principal who has been serving a 99-year prison sentence for the 1985 murder of his wife. His conviction was based in part on the testimony of an expert witness in blood spatter interpretation.

The blood spatter testimony indicated that the weapon used was a .357, like the one that Bryan owned. The prosecution stated that a flashlight found in Bryan’s car days after the murder contained small drops of the victim’s blood, although only presumptive tests were conducted. The blood spatter analyst testified the killer held the flashlight as he shot from close range.

Bryan continues to assert his innocence and an evidentiary hearing was held last month in which his attorney argued – backed by the testimony of a crime scene investigator – that the blood spatter testimony presented at trial was scientifically unsubstantiated. The hearing is currently in recess, awaiting the results of DNA testing on the flashlight that are expected to come back sometime in the fall.

In May, Pamela Collof published a two-part article describing in-depth the background of the case and the testimony of the blood spatter expert witness. The articles are available at: https://features.propublica.org/blood-spatter/mickey-bryan-murder-blood-spatter-forensic-evidence/ (Part I) and https://features.propublica.org/blood-spatter/joe-bryan-conviction-blood-spatter-forensic-evidence/ (Part II).

Brandon Garrett

September 7, 2018

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The Pseudoscientific Practice of Blood Spatter Analysis How the Desire for Convictions Drives Flawed Prosecutions

by Anthony W. Accurso

The forensic science known as Bloodstain Pattern Analysis (“BPA”)—a.k.a. blood spatter analysis—is undergoing significant development after being the object of intense criticism regarding its reliability in the context of criminal prosecutions. Despite being practiced for over 150 years, this field has undergone two periods of dramatic change: first, in the mid-twentieth century, practitioners sought to standardize and popularize the application of BPA in courtrooms, and second, since the dawn of the twenty-first century, scientists and policymakers have sought to reform its application through better scientific understanding and rules to lessen the likelihood of flawed prosecutions.

Yet, the utility of blood spatter analysis in prosecuting emotionally-charged, violent crimes often puts its most frequent practitioners—law enforcement officers who often receive as little as 40 hours of training—at odds with the uncertainties inherent to a still-developing science. This conflict results in forensics “experts” opining on blood pattern evidence in criminal trials, despite lacking a solid scientific foundation for the conclusions they reach yet authoritatively testify before juries. Thus, while claiming the authority of science to persuade juries about the guilt (or sometimes innocence) of a defendant, these “experts” risk peddling unreliable pseudoscience, resulting in the subversion of justice. The result is that an innocent person can spend decades in prison for crimes they did not commit, while the actual perpetrator remains at large, free to commit more violent offenses.

Some of these failures have been publicized in a way that drew attention to the (mis)use of BPA in courts and prompted reforms. How these failures unfold can be illustrated by the case of David Camm.

Eight Flecks of Blood

Around 7 p.m. on the evening of Sep. 28, 2000, David Camm arrived at the Georgetown Community Church in his hometown of Georgetown, Indiana, to play basketball. David was a former Indiana State Trooper who went out to shoot hoops with 11 other guys around the time his wife and children were returning home from swim practice.

Later that evening, at around 9:30 p.m., David returned home to a horrific scene: his wife, Kimberly, and their two children, Bradley (age 7) and Jill (age 5), had been shot to death in the family’s garage.

Floyd County law enforcement documented the scene of the crime, including having photographer Robert Stites take pictures of all the blood evidence. Among these photos was a shot of the t-shirt worn by David that evening, which bore eight flecks of blood in a small grouping.

The BPA specialist used by Floyd County was Rodney Englert. Though he did not visit the scene of the murder, Englert concluded from the photo of Camm’s t-shirt that the pattern of blood on it was “backspatter”—stains created from a high-velocity impact that deposited on the shirt when its wearer was near the victim(s) during the shooting.

Three days after losing his wife and children, David Camm was charged with their murder. Englert’s interpretation of the eight flecks of blood would not only be the chief piece of evidence upon which the State’s case rested, it also largely drove the police investigation from that point forward.

How this small amount of blood came to be so influential is wrapped up in the history of BPA as a forensic science, and its acceptance in court systems around the country.

Macabre Experiments

While the first mention of blood spatter at trial comes from an 1880 Mississippi Supreme Court decision it wasn’t until the middle of the twentieth century that BPA was officially admitted as an area of expertise in criminal trials.

Dr. Paul Leland Kirk first testified about the significance of blood evidence in 1954 in the case of Sam Sheppard, an Ohio doctor accused of murdering his wife.Dr. Kirk was a renowned biochemist who, after working on the Manhattan Project helping the U.S. develop its first nuclear weapons, turned his significant scientific expertise toward the field of criminology and established a first-of-its-kind academic program in criminalistics at the University of California at Berkeley in the 1950s.

Sheppard’s attorney hired Dr. Kirk to review the blood spatter evidence, and Kirk offered an interpretation of the events that the defense believed exonerated Sheppard. Though he was convicted at his first trial, Sheppard was acquitted at his retrial in 1966, largely because of Dr. Kirk’s testimony.

Shortly after Sheppard’s first trial, Dr. Kirk also testified in People v. Carter 312 P.2d 665 (Cal. 1957), a case involving a California man who was accused of beating to death the owner of the Log Cabin Bar in Chico. Though this was only his second time testifying, the California court admitted Dr. Kirk as an expert in BPA, and this classification was upheld on appeal in 1957.

In that decision, the California Supreme Court stated: “Dr. Kirk was permitted to testify that he made certain experiments in blood dynamics: that he had beaten bloody objects with instruments of different shapes in order to grasp the relationship between blood spots and their causes.” This record was “introduced to qualify him as an expert in blood dynamics, to show that by training and experience he was able from an analysis of the size and shape of blood spots to determine their source with some degree of accuracy, and to enable the jury to test the reliability of his opinions by revealing their foundation.”

Dr. Kirk testified that the blood patterns at the scene of the crime enabled him to infer where in the bar the victim had been beaten and that the defendant “must have been not more than two and one-half feet from the source of the blood.”

The Court concluded that, “[t]hese inferences required knowledge and experience beyond those of ordinary jurors and could assist them to weigh the evidence more perceptively than they could unaided.”

It was also in the 1950s that the greatest proselytizer of BPA got his first taste of its possibilities. Herbert MacDonell was a chemistry undergraduate who got a job in a Rhode Island state crime laboratory. MacDonell would later move to Corning, New York, to work for the local corporate giant, Corning Glass Works—a company best known for CorningWare casserole dishes and the Gorilla Glass that provides sturdy screens for modern smartphones. MacDonell worked for Corning during the day while teaching crime lab forensics at night at a community college.

This expertise in forensic science brought him to testify in a New York murder trial in 1968. Steven Shaff, a veterinarian, had shot a former employee and claimed it was an accident. Investigators alleged that Shaff shot the victim in his vehicle, but Shaff claimed the victim had thrown open the vehicle’s door, causing Shaff’s gun to discharge. Though MacDonell’s expertise had the limited use of pointing out that blood present along the inside edge of the car door (where it joins with the door frame) could only have been deposited there while the car door was open, this case ignited MacDonell’s imagination for the possibilities of blood spatter evidence.

MacDonell constructed a lab in the basement of his home and conducted macabre experiments with blood—similar to the ones described by Dr. Kirk—to further his expertise. According to ProPublica “he described shooting dogs to record the resulting spatter and drenching a female student’s hair in human blood then having her shake it around to photograph the patterns.”

A year after testifying in the Shaffcase, MacDonell got the Department of Justice (“DOJ”) to fund his work. This culminated in his 1971 report, published by the DOJ, “Flight Characteristics and Stain Patterns of Human Blood.”

It should be noted that, even though Dr. Kirk and MacDonell had been conducting “experiments,” their activities were merely setting the stage for a true scientific analysis of blood patterns in forensics. MacDonell acknowledged this in the opening to his 1971 report, stating: “[f]inal conclusions should be considered from the legal viewpoint of ‘proof within a reasonable scientific certainty.’ Little attempt has been made to express data in this report in a statistical manner.”

Despite acknowledging the qualitative, rather than quantitative, nature of his work, MacDonell began traveling to conferences and industry meetings to present his research. This spread the word about his claims to be able to derive meaning from patterns of blood, and he was more frequently hired by police and prosecutors to consult on, and testify about, blood spatter evidence. He soon quit his job at Corning Glass in favor of working full time as an instructor and forensic expert for hire.

In 1973, he began teaching a 40-hour class he dubbed “Bloodstain Evidence Institutes.” Rather than hire MacDonell to consult on every violent crime in the country (Dr. Kirk diedprior to the publication of MacDonell’s DOJ report, and few other researchers publicized their willingness to testify in this area), police departments preferred to have a trained “expert” on staff to analyze cases.

Though he would emphasize his own scientific background when called to testify, MacDonell would advertise to his students that there were “no minimum educational requirements to be accepted into the class.” In an interview with a reporter for ProPublic, MacDonell could recall failing only five students in his 38 years of teaching classes, compared to the more than 1,000 students he taught. Also, according to ProPublica, “[b]y 1982, [he] taught 19 institutes in eight states (Mississippi, New York, Florida, Alabama, Indiana, Illinois, Louisiana and Colorado)” and “gave single-day seminars in Germany, Italy, England, Switzerland and Canada.”

MacDonell later taught what he called “advanced” classes, and the graduates of these classes would go on to form the International Association of Bloodstain Pattern Analysts (“IABPA”) in 1983. The group would subsequently begin publication of its Journal of Bloodstain Pattern Analysis —similar to how other scientific fields have published peer-reviewed journals.

By the late 1980s, MacDonell was becoming something of a superstar in the forensics world. A 1987 three-part series about MacDonell referred to him as “an American Scotland Yard, all by himself”—a quote lifted straight from the back of his coauthored memoir, The Evidence Never Lies: The Casebook of a Modern Sherlock Holmes .

It was against this background that the Iowa Supreme Court upheld MacDonell’s certification as a reliable expert with regards to BPA in State v. Hall , 297 N.W.2d 80 (Iowa 1980). The Court stated, in regard to BPA, that “the study of blood characteristics is relatively uncomplicated,” and its “observations are largely based on common sense, and in fact, lie close to the ken of an average laymen”

Regarding the reliability of MacDonell’s methods, the Court pointed to: “(1) Professor MacDonell’s considerable experience and his status as the leading expert in the field; (2) the existence of national training programs; (3) the existence of national and state organizations for experts in the field; (4) the offering of courses on the subject at several major schools; (5) use by police departments throughout the country in their day-to-day operations; (6) the holding of annual seminars; and (7) the existence of specialized publications.”

What the Court does not mention, according to reporting by the New York Times , is that “MacDonell himself is the source of almost all of these indicators of reliability.” Indeed, as state after state upheld the use of BPA experts as reliable interpreters of evidence in criminal trials, nearly every case involved MacDonell or someone he had trained or referenced such a case when deferring to another court’s determination.

Thus, while Dr. Kirk was the first expert certified by a state court to testify on BPA, MacDonell and his students were responsible for its spread and acceptance in a majority of jurisdictions in the United States. In 2004, a Texas court of appeals wrote: “Have any courts held blood spatter analysis to be invalid? The short answer is no.” Holmes v. State , 135 S.W.3d 178 (Tex. App. 2004).

MacDonell would continue to testify until 2012 when he was charged in Corning Town Court with forcible touching, two counts of endangering the welfare of a child, exposure of a person, and aggravated harassment in the second degree, all stemming from the alleged sexual abuse of two young girls, ages 11 and 16. He pleaded guilty to the harassment charge in exchange for the state dropping the other charges, though he later publicly expressed regret over the decision while claiming his innocence. But this conviction meant that he could no longer testify in court because his credibility would be too easy to undermine on the witness stand.

However, by the time MacDonell retired, he had certified over 1,000 of his students in BPA. And unlike Dr. Kirk—who had enough scientific training to contribute to the Manhattan Project—and MacDonell—who had at least a chemistry degree and himself taught at the college level—these trainees in the field of BPA were mostly law enforcement professionals with little or no scientific background, many of whom lacked a basic understanding of the alleged science underpinning their methods. And even more troubling is that some of these trainees themselves began teaching classes on the subject.

“I think if you were to do a study,” Ralph Ristenbatt, an instructor of forensic science at Pennsylvania State University, said, “of all the people who call themselves bloodstain-pattern experts and you looked at the genealogy, if you will, of how they’ve obtained their training, it’ll all likely come back to Herb MacDonell through some means.”

Pseudoscientific Practice Versus Scientific Study

At David Camm’s first trial, the State’s BPA expert, Rodney Englert, provided key testimony that the eight flecks of blood on Camm’s shirt were consistent with “high-velocity impact spatter,” a pattern he claimed could only have occurred if Camm were nearby his wife and children when they were shot

However, Camm’s defense attorney hired their own BPA expert who—after reviewing the same evidence as Englert—concluded that the blood on the shirt was a “transfer stain,” deposited by his daughter’s hair when he tried to save his children.

Later, at his retrial in 2013, forensic scientist Robert Shaler testified that the stain’s meager size was “too little information from which to draw any meaningful conclusion.”

The disparity of interpretations by various BPA experts speaks to the central issue at play: Though BPA started out like many other fledgling fields of scientific inquiry, its current practitioners are more pseudoscientific—they try to appear scientific despite lacking sufficient training and experience, all while peddling unfounded confidence to juries and derailing the pursuit of justice.

But it turns out that, as shocking as this truth is, BPA is not alone among forensic “sciences” facing harsh criticisms about their reliability.

The systemic failure of forensics was revealed after the advent of DNA testing—the gold standard of forensic science—when the retesting of evidence began to overturn convictions. Crediting the Innocence Project, ProPublica concluded that, “[o]f the 250 DNA exonerations that occurred by 2010 throughout the United States, shoddy forensic work—which ranged from making basic lab errors to advancing claims unsupported by science—had contributed to half of them.”

As the mounting number of exonerations exposed the sorry state of forensics in the United States, calls intensified for a systemic review of various fields that had long been criticized as pseudoscientific. This prompted the federal government to conduct an in-depth analysis of the state of the science underpinning the fields of forensic practice.

The first major report bearing on BPA was published in August 2009 by the National Academy of Science—a private, non-profit organization created by the U.S. Congress in 1863 with the mission to advise the nation on science, engineering, and medicine. The report, titled “Strengthening Forensic Science in the United States,” was a devastating shot across the bow of the forensics community.

The portion of the report focusing on the reliability of various forensic fields classified them largely into two categories: laboratory based (e.g., DNA analysis, toxicology, and drug analysis) and those based on the “interpretation of observed patterns” (e.g., fingerprints, writing samples, tool marks, bite marks, and specimens such as fibers, hair, and fire debris).

It stated that “[t]he level of scientific development and evaluation varies substantially among the forensic science disciplines,” and leveled its harshest criticisms against the pattern interpretation disciplines.

Even ones that had been near-universally accepted by those within the criminal justice system were questioned. Friction Ridge Analysis—commonly known as fingerprint comparison—is accomplished by the ACE-V method (“Analysis, Comparison, Evaluation, and Verification”). The report stated that ACE-V “is not specific enough to qualify as a validated method”; “does not guard against bias; [and] is too broad to ensure that two analysts following it will obtain the same results.”

Hairexamination has long suffered from a lack of scientific rigor, and the report concluded that, “due to the fact that so many of the characteristics coded are subjective—for example, color, texture—it was not possible to get complete reproducibility between two or more examiners coding the same hair.” The report’s authors cautioned against ever trusting a claimed hair sample match based on visual examination alone, saying, “[i]n cases where there seems to be a morphological match (based on microscopic examination), it must be confirmed using mtDNA analysis; microscopic studies alone are of limited probative value.”

Subsequently, in 2015, the FBI admitted that two dozen examiners in one of its hair analysis labs had given flawed testimony in hundreds of cases. Of these, 32 defendants had been sentenced to death, and 14 of them were eventually executed or died in prison, according to Reason.

BPA was similarly criticized with the bottom-line assessment being that “[t]he uncertainties associated with [BPA] are enormous” and “that some experts extrapolate far beyond what can be supported.” The report notes that some aspects of BPA are supported by scientific studies—“for example, if blood spattered quickly or slowly.” Other conclusions lack a scientific underpinning, with the report stating that, “[a]lthough the trajectories of bullets are linear, the damage that they cause in soft tissue and the complex patterns that fluids make when exiting wounds are highly variable.”

While forensic disciplines such as Forensic Odontology (bite mark analysis) and Polygraphy (lie-detector tests) have “no scientific support” for the claims made by their practitioners, the DOJ was confident enough in the basis of BPA that it funded a follow-up study whose purpose was “to produce the first baseline measure of reliability for the major BPA method of pattern recognition”

“Reliability Assessment of Current Methods in Bloodstain Pattern Analysis” was published in June 2014 by the National Institute for Justice (“NIJ”), the research arm of the DOJ. The study’s authors invited 27 analysts from North America, Australia, and Europe to identify various patterns created by the research team. All of the analysts had at least 80 hours of training, had been active in BPA casework for a minimum of five years, and had been qualified by a court as a BPA expert to provide testimony. The results were quite damning.

The team produced various stains—drip patterns, transfer patterns, blunt force impact spatter, cast-off patterns, and firearms-related patterns (both back spatter and forward spatter)—onto 16 inch by 16 inch tiles, representing hard surface targets (painted, wallpaper, and chipboard) and fabric surface targets (polyester pants, blue denim jeans, and grey cotton sweatpants).

The study’s authors noted limitations in their methods, notably that some of the stains were produced under “ideal” conditions—meaning that these patterns were less “messy” than real-world examples and should thus be easier to identify, making them less representative of analysts’ competency when conducting actual casework. The team said the “approach used here was designed to help define the upper limit of pattern classification reliability by focusing attention on method reliability rather than on analyst competency.” (emphasis in original).

Even with these caveats in place, the results were stunning. When presented with open-ended pattern identification scenarios, over half of the responses were labeled “inconclusive.” Of patterns where a classification was attempted, there were success rates of “close to [] 50%” and 64% for hard surfaces and fabric surfaces, respectively. When presented with multiple choice responses, the patterns listed as inconclusive dropped to 17% and 14%, where 14% and 23% “of these classifications did not include the correct pattern type,” again listed respectively with hard surface and cloth targets

Aside from troublingly large rates of unclassified or misclassified patterns, the study’s authors noted two more structural problems with BPA methodology.

The first is that pattern analysis is often performed by investigators involved with other aspects of the case—recall that many experts certified by MacDonell were police—which “means that at the stage of pattern classification, additional case-specific information, such as medical findings, case circumstances and even witness testimony is being allowed to factor into analysts’ interpretations.”

This leads to “the well-known phenomenon of confirmation bias. Where a scenario was offered that deliberately pointed analysts towards an incorrect classification, the proportion of misclassifications that resulted was significantly higher than that observed for patterns with neutral scenarios.”

The authors say this issue is compounded by the second structural problem, “that current pattern classifications used in BPA are described in terms of pattern formation mechanisms, which actually makes them components of a reconstruction theory, rather than a summary of pattern characteristics.”

This poses a significant challenge to reliability because, as the study authors noted, “[i]t is well known that different bloodletting mechanisms can give rise to bloodstain patterns that possess similar or indistinguishable characteristics” For instance, “impact, expiration and transfer patterns can all feature small bloodstains and can be confused with one another, especially on fabric.” This means that an analyst, with insufficient training or who is influenced by misleading case details, may fail to accurately distinguish a bloodstain on a suspect’s clothing as being deposited during an attempt to resuscitate a victim, versus being deposited when the suspect beat the victim with a blunt object—two scenarios that speak to diametrically opposite courses of action.

A similar finding was included in a report written by New York criminal defense attorney Michael Litman, which said that “the exact same blood spatter trajectory would appear very differently when it hits an absorbent material (such as a bedsheet) as opposed to a non-absorbent material (such as a solid wall). It has been found that when blood spatters on absorbent materials, the patterns can appear distorted and lead forensics scientists and investigators to misinterpret the direction from which the blood traveled.”

The most recent, comprehensive review of forensic sciences was a 2016 report by the President’s Council of Advisors on Science and Technology (“PCAST”), a group organized at the direction of President Obama to review the use of forensic sciences in criminal prosecutions.

The group found that several common forensic methods “have revealed a dismaying frequency of instances of use of forensic evidence that do not pass an objective test of scientific validity.” For instance, with regards to bite mark analysis, the report said that “available scientific evidence strongly suggests that examiners not only cannot identify the source of [a] bite mark with reasonable accuracy, they cannot even consistently agree on whether an injury is a human bite mark.” The report was no less scathing in its review of BPA, saying, “[o]ur results show that conclusions were often erroneous and often contradicted other analysts.” Also, “[b]oth semantic differences and contradictory interpretations contributed to errors and disagreements, which could have serious implications if they occurred in casework.”

The 2014 NIJ study assessing the reliability of BPA observed that, “[l]ike many other disciplines from the early days of forensic science, its use and acceptance occurred without rigorous validation,” because “very little is known about [BPA’s reliability] beyond the instincts of experienced instructors and investigators who have observed over many crime scene and practical sessions in the classroom.”

Similar studies have attempted to statistically validate error rates in bloodstain-pattern recognition, but each of these acknowledges that lab-created blood patterns made using materials crudely analogous to victims’ bodies (such as shooting a blood-soaked sponge with a pellet gun) fail to capture the complexities of real crime scenes and that “it is generally impossible to know with certainty the ‘true’ mechanistic cause of a bloodstain pattern at a crime scene.”

It was with these limitations in mind that the PCAST report recommended expert witnesses be required to “disclose error rates in their testimony and, where methods haven’t been scientifically verified, not use them at all,” according to Reason .

While the Obama administration took no firm steps to implement this recommendation, the Trump administration’s response was openly hostile. According to Reason “[i]n 2017, Attorney General Jeff Sessions disbanded the National Commission on Forensic Science, an independent panel of scientists, law enforcement, judges, and defense attorneys created by the Obama administration in 2013 to review the reliability of forensic science used in trials.”

Sessions then replaced it with the Forensic Science Working Group—headed by a former state prosecutor—with the more limited mission of developing “uniform language” for federal experts’ testimony. After Sessions stepped down, Deputy Attorney General Rod Rosenstein complained that “forensic science has been under attack” by critics who took “an erroneously narrow view of the nature of science and its application to forensic evidence.”

The different attitudes reflected in the reactions of the Obama and Trump administrations mirror the two predominant attitudes present within the U.S. population when people are faced with pseudoscientific claims. Confronting the inconvenient truth that a valuable tool used in police work (BPA) was unreliable, the Obama administration tried to determine what about BPA was salvageable by funding studies into the field’s limitations—a long-term strategy that would take time but would ultimately increase the public’s confidence in BPA’s use by determining what about BPA was legitimately grounded in science.

The Trump administration’s response was to value the usefulness of BPA (and other forensic sciences) in securing convictions and to silence rigorous scientific review in favor of this prosecutorial value. Though this dichotomy is playing out in our predominate political parties, it is further mirrored in attitudes of real Americans.

Take astrology for instance. Peddlers of horoscopes claim that the movements of planets, moons, and stars have definite and predictable effects on the lives of individuals and that these effects relate somehow to a person’s birth date (or birth minute, depending on the peddler).

This is clearly pseudoscientific for three reasons, though any one of them would be enough to classify astrology as unscientific: (1) there is no plausible mechanism that has been identified that would cause these effects; (2) there is no error-correcting method by which practitioners can improve their predictions; and (3) the predictions made are often too vague to be tested, or when they are specific enough, are no better at predicting outcomes than random chance.

Yet, according to an Insider poll, a full 13% of Americans believe astrology to be credible. This means that nearly 43 million of our neighbors believe in horoscopes, and many of these people will make decisions based on this belief.

Most people do not believe in astrology but say little about it because it has no perceptible effect on their lives. Fortunately, this pseudoscience is generally harmless.

Tragedy arises when unfounded belief in pseudoscience has real and devastating consequences for others. Most American have no vested interest in whether the practice of BPA is grounded in science because it will never affect their lives. For persons charged with a violent crime—especially innocent persons—the confidence a judge and jury place in a BPA expert can have life-changing consequences.

“An expert who says, ‘This is what the physical evidence shows,’ is extremely persuasive, especially in a criminal case,” said Judy Royal, a staff attorney with the Center on Wrongful Convictions, to ProPublica. “Jurors don’t understand when an expert is overstating findings or going beyond what can be tested and replicated.”

‘A Judge Should Be Able to Recognize Unqualified Charlatans’

Our criminal court system is supposed to be the way that our society collectively determines the truth of our history as it relates to violations of the social contract. As such, we expect it to have a mechanism for determining the reliability of evidence provided by the opposing parties. The system does have such a mechanism, but it is deeply flawed and reflects Americans’ historically ambiguous relationship with science.

In detailing this flaw, we must first recognize that we have not one court system but rather an overlapping patchwork of court systems. The criminal courts in each state and federal judicial district will often share best practices, but they don’t always agree on what constitutes the “best.”

Courts in general have rules about who is allowed to interpret evidence for a jury. It is seen as generally preferable to present evidence to the jury directly, but juries cannot always be expected to possess the knowledge and experience in every field of inquiry. Consequently, experts are allowed in court to present their opinions.

For instance, Idaho Rule of Evidence 702 states: “If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skills, experience, training, or education may testify thereto in the form of an opinion or otherwise”

The commentary on this rule states: “Because of the rules’ emphasis on liberalizing expert testimony, doubt about whether an expert’s testimony will be useful should generally be resolved in favor of admissibility.... Expert testimony may also be excluded when it would confuse the jury, be more prejudicial than probative, or be needlessly time-consuming.”

Though these specific examples come from Idaho, they are representative of the analogous rule present in courts all across the country.

The way this plays out then is that one party puts forward a witness for the purposes of interpreting some piece of evidence. That party states the qualifications of the witness in relation to the evidence, while the opposing party attempts to argue that those qualifications are insufficient. In the end, the judge will determine whether the witness is sufficiently qualified.

Given the proliferation of scientific disciplines, as well as practitioners of pseudoscience, some courts in the modern era have sought to establish a review of more than just an expert’s qualifications and instead look at whether the methods underlying their analysis are sufficiently scientific to justify their conclusions.

For courts seeking to adopt a more thorough analysis of the underlying science, many have adopted the test from Frye v. United States , 293 F. 1013 (D.C. Cir. 1923). The Frye Court was faced with the decision whether to approve testimony by a polygrapher about the lie-detector test performed on the defendant.

In determining that the polygraph was insufficiently reliable to admit into evidence, the Court said the following: “Just when a scientific principle or discovery crosses the line between the experimental and demonstrable stages is difficult to define. Somewhere in this twilight zone the evidential force of the principle must be recognized, and while courts will go a long way in admitting expert testimony deduced from a well-recognized scientific principle or discovery, the thing from which the deduction is made must be sufficiently established to have gained general acceptance in the particular field in which it belongs.”

A review by the Court of the scientific community at the time of the Frye decision showed no consensus that the polygraph could reliably do what its practitioners claimed—that it could distinguish truth from lies. In the intervening 100 years, no court has found otherwise, and polygraph results are generally inadmissible as proof of guilt. Yet this does not stop investigators from subjecting suspects to these tests because law enforcement officers generally believe in this pseudoscientific device despite multiple studies that have shown it to be no better than chance at detecting lies.

The wisdom of the Court’s decision in Frye is that the U.S. Court of Appeals for the D.C. Circuit recognized the difficulty faced by judges in determining whether a scientific expert is credible, especially when these judges lack sufficient scientific training themselves. The Court therefore chose to offload the problem to the scientific community—basically, the expert’s peers. Thus, if sufficient scientific studies have been published that validate the method used by a proposed expert, and the expert is sufficiently qualified, then their opinion may be presented to the jury.

However, not all courts have adopted the Frye standard. Some courts, such as in the state of Idaho, have specifically rejected additional admissibility rules for evidence, preferring instead to trust judges to make these decisions on a case-by-case basis.

This is troubling because there is no reason to believe that judges are any better at sorting credible scientific theories from pseudoscience than the general public, even when assisted in the task by attorneys. In a country where approximately 6 million people believe the Earth is flat—again, according to Insider should we really allow judges alone to make this decision?

In addition to the problem of judges not having sufficient scientific training, courts often fail to weed out pseudoscience, relying on the findings of other courts to guide them. This practice is called “precedent,” and while it works well enough for matters of legal importance, it fails as a method of excluding pseudoscientific claims.

“Precedent is like a child’s game of telephone,” federal Judge Nancy Gertner said in a statement to ProPublica. “You start off saying something. You whisper it down the line and you continue to whisper it even though it no longer makes sense.”

The first few courts to uphold the admittance of BPA either rejected Frye , failed to apply it correctly, or were too dazzled by the claims to expertise of Dr. Kirk and Herbert MacDonell. And MacDonell could dazzle an audience. ProPublica described the “strange sight in the 1985 Texas courtroom, [where] the jurors, the judge and even the defense attorneys watched, rapt, as MacDonell laid the mirror flat and then climbed up on a chair, holding the vial and dropper,” and proceeded to drip blood on the mirror. This had been hastily borrowed from the courthouse bathroom, and the vial contained MacDonell’s own blood, drawn earlier that day at a nearby hospital.

Subsequent courts would look to these decisions to admit BPA evidence and conclude that it “is considered a proper subject of expert testimony.”

A Texas Court of Appeals concluded in 1987 that MacDonell’s testimony was admissible by stating, “MacDonell’s studies are based on general principles of physics, chemistry, biology, and mathematics, and his methods use tools as widely recognized as the microscope; his techniques are neither untested nor unreliable.” Lewis v. State , 737 S.W.2d 857 (Tex. App. 1987).

In light of recent criticisms of BPA and studies demonstrating the clearly unreliable results proffered by many of its experts, the statement of the Court of Appeals in Lewis amounts to a monumental failure akin to saying that an expert is trustworthy because they wear a lab coat and regularly use a microscope.

MacDonell was not able to dazzle everyone, despite his best efforts. In his dissent in the 1980 decision of the Iowa Supreme Court in Hall Judge Mark McCormick wrote, “I am unable to agree that reliability of a novel scientific technique can be established solely on the basis of the success of its leading proponent in peddling his wares to consumers.”

Similarly, in his dissent to the Idaho Supreme Court’s decision in State v. Rogers , 812 P.2d 1208 (Idaho 1991), Judge Stephen Bistline wrote: “The danger presented by expert testimony interpreting blood-spatter evidence is that the prosecution is provided with an expert who appears to be able to reconstruct precisely what happened by looking at the blood left at the scene of a crime. However, a quick review of the ‘science’ relied upon by the expert suggests that we would be better off proving guilt beyond a reasonable doubt without the help of such experts.” (emphasis in original)

But these judges were the dissenters on panels of judges that otherwise approved of BPA experts. Once these courts of appeals signed off on allowing BPA into courtrooms, precedent—and a few courtroom performances by MacDonell or his students—allowed this forensic pseudoscience to spread through court systems like a virus

Trial courts often now routinely admit BPA experts on their stated qualifications alone, often with little argument from defense attorneys.

“If the courts routinely admit junk science,” Judge Gertner, said, “the lawyer with a finite amount of resource is not about to say I will spend this dollar on a challenge if it’s not going to make a difference.”

In an ironic twist, MacDonell himself has been hired on several occasions to refute interpretations of BPA evidence proffered by his former students. He responded to the criticism that he paved the way for unqualified persons to testify in courts around the country by stating in one of his books, “[t]he fault for permitting such individuals to testify as an expert must rest with the opposing attorney” and added that “a judge should be able to recognize unqualified charlatans.”

Turning back to the case of David Camm, several BPA experts signed an ethics complaint in 2003 with the American Academy of Forensic Scientists, claiming that Rodney Englert misrepresented his education, training, and experience. Among them was MacDonell, who referred to Englert as “a forensic whore,” a “liar-for-hire,” “a very smooth charlatan,” and “[t]he Bin Laden of Bloodstains.”

All of these experts expressed opinions in support of David Camm’s innocence, and all of them were sued by Englert for slander.

‘As Accurate as a Ouija Board’

Despite decades of criticism leveled against BPA, including damning government reports and validation studies that show alarming error rates, workshops are still being taught that certify attendees as so-called experts. After a short period of informal apprenticeship to establish the requisite experience, workshop attendees can often meet the minimum requirements to testify as an expert in a criminal trial.

Police investigators who receive this certification will testify on behalf of the State during a criminal trial, saving the State money by not having to outsource its expert witnesses. This savings is no small amount either. Depending on the nature of a person’s expertise and the amount of time spent on the case—including travel and time in the courtroom—such experts can cost the State thousands of dollars per case. And when a certified BPA expert is hired by a defense attorney, the expert themselves will personally profit from these consulting fees. They can earn still more money by teaching these questionable skills to others, like MacDonell did.

This is clearly a viable and profitable business model, as MacDonell was able to support his family on an income solely based on consulting and teaching. There appears to be few hurdles standing in a person’s way when considering such a career.

The 2009 NAS report stated that “the interpretation and reconstruction of blood stains requires at minimum, an understanding of applied mathematics, the physics of fluid transfer, and the pathology of wounds.” Most graduates of BPA workshops like those operated by MacDonell are police officers who lack this background in science, and the NAS has specifically said that these workshops are not an adequate substitute for a scientific background with appropriate training, experimentation, and experience. The NAS was further critical of certifications awarded to trainees based on a minimum number of hours spent in a class, because these persons regularly fail to demonstrate a mastery of the “rigorous and objective hypothesis testing” and “complex nature of fluid dynamics” that is “essential to the formation of reliable opinions about the cause of blood patterns.”

Despite these criticisms, governments have mostly failed to make any regulatory changes in this area, so becoming a BPA expert, earning consulting fees, and passing on these skills is as easy as ever.

Tom Bevel spent nearly three decades in the Oklahoma City Police Department, where he developed an interest in blood spatter. He attended both the 40-hour basic and the 80-hour advanced courses taught by MacDonell. He was also the first president of the IABPA. These achievements were endowed despite Bevel having no advanced degrees in any scientific field relating to BPA nor any other significant scientific training. He regularly contracted his services as a BPA expert, most often testifying for the prosecution.

Bevel was a co-founder of Bevel, Gardener & Associates, an Oklahoma firm that conducts BPA training workshops similar to MacDonell’s. His partner in this venture, Ross Gardner, was also his co-author on the textbook, Bloodstain Pattern Analysis with an Introduction to Crime Scene Reconstruction, 3rd Edition . Though it should be noted that Ralph Ristenbatt, the previously mentioned instructor of forensic science at Penn State, stated in a review of Bevel and Gardner’s textbook that it “lacks scientific integrity.”

Bevel has also testified or consulted for the prosecution in several high-profile cases where his interpretation of BPA evidence was criticized or controverted by analysts with more scientific training.

Bevel was one of several analysts who consulted on David Camm’s caseand sided with Englert in his flawed and unfoundedly confident interpretation regarding Camm’s guilt, according to an organization called Investigating Innocence. Camm, as will be explained in more detail, was eventually acquitted on retrial.

Bevel was also the lead analyst of blood spatter evidence in the trial of Warren Horinek, a former Fort Worth, Texas, police officer accused of shooting his wife on the night of March 14, 1995. The investigators and analysts initially agreed with Horinek that his wife committed suicide, and the district attorney refused to press charges against him. His wife’s family hired their own private attorney and investigator, and they used a legal loophole in Texas to bring evidence before a grand jury.

At trial, it looked as though Horinek would prevail, at least until Bevel took the stand and confidently asserted that a minute amount of blood on Horinek’s nightshirt had to originate from a “high-velocity occurrence,” such as a gunshot, instead of being expirated by his wife while he performed CPR on her, as he claimed.

After Horinek was convicted and sentenced to 30 years in prison, one juror stated that it was Bevel’s testimony that turned the jury.

Subsequently, based on a request from one of the police officers involved in the case, the evidence was reviewed by MacDonell and Anita Zannin—a prominent lab analyst who worked with MacDonell—both of whom concluded that Bevel’s conclusion was utterly incorrect, because there was no way to determine whether the blood pattern was the result of CPR or a gunshot.

Horinek is still in prison, despite efforts to overturn his conviction. He will be eligible for release in 2026.

Bevel was also responsible for teaching Robert Thorman during a BPA workshop in 1985, and Thorman would testify that year in the trial of Joe Bryan—a Huntsville, Texas, high school principal accused of shooting his wife, Mickey, an elementary school teacher. Though no other evidence linked Bryan to the scene of the crime—he was attending a conference out of town the night his wife was murdered—Thorman testified that minute flecks on the lens of a flashlight found in Bryan’s trunk could have only been high-velocity backspatter, deposited there when Joe shot Mickey. Bryan was convicted at trial and sentenced to 99 years in prison.

A subsequent review of the evidence by professionals with more scientific training than Thorman—including Ralph Ristenbatt, the Penn State professor—concluded Thorman’s theory of the crime was “totally specious, and there’s no evidence to support it.”

In 2011, an attorney for Bryan obtained evidence from the case to have it tested for DNA. The report concluded that the partial profile on the lens of the flashlight “was too limited for a meaningful interpretation.” Yet one line in the report stood out: “A presumptive test for blood was negative on the lens.”

After learning that the flecks on the flashlight were not blood, Thorman publicly acknowledged that his conclusions were unsustainable. However, convictions are notoriously difficult to overturn in Texas, and Joe Bryan was eventually paroled March 31, 2020, after serving 33 years in prison. The Innocence Project of Texas filed a petition that same year asking the U.S. Supreme Court to overturn his conviction.

In a Connecticut case, EverettCarr was brutally stabbed 27 times in his own home on the morning of December 2, 1985. Teenagers Ralph Birch and Shawn Henning somehow became the lead suspects in the case despite having no apparent connection to the crime. The teens were found sleeping in a vehicle they had stolen—not a good way to begin an interaction with law enforcement—though none of Carr’s blood was found in the vehicle or on the boys.

BPA expert Henry C. Lee testified at their 1989 trial that bloodstains found on a towel in Carr’s home were deposited in a way that was consistent with Carr’s blood spraying away from the assailants, explaining why they weren’t covered in Carr’s blood when they were found.

Thirty years after the teens had been convicted at trial, the Connecticut Supreme Court vacated their convictions because subsequent retesting of the towel revealed that the stain wasn’t even blood.

By the time the teens’ convictions were overturned, Lee had been a BPA expert for over 50 years and investigated over 8,000 cases, including the murder trial of O.J. Simpson.

He also took part in the investigation of the alleged murder of Lana Clarkson in 2003 by renowned music producer Phil Spector. According to two of Lee’s former colleagues, Lee picked up part of an “acrylic fingernail” at the murder scene and placed it in a vial. Four years later, the trial court ruled that Lee willingly failed to turn over the object—reports alleged that he hid or destroyed it—despite it being crucial to proving that Clarkson could not have committed suicide.

In another example from Texas, analystRodney Englert made an appearance in another high-profile case—the murder of 10-year-old Joel Kirkpatrick in the early morning hours of October 13, 1997, in Lawrenceville, Texas. His mother, Julie Rea, awoke to screams in the night. After checking Joel’s room and not seeing him in bed, she ran through the house until she confronted an armed intruder. The two engaged in a protracted struggle where Rea was injured and the assailant escaped. She then sought help from a neighbor who called the police.

Investigators failed to find evidence of forced entry, and the knife from Rea’s kitchen used to stab Joel yielded no fingerprints. Without any clues to go on, investigators became suspicious of Rea, a single mom recently divorced.

Englert, reviewing the blood-spatter evidence from the scene concluded that the crime scene had been “staged and manipulated” and was “not consistent with her story of a struggle.” During his testimony at Rea’s trial, Englert put on a show for the jury, explaining BPA’s basic principles while performing a lengthy demonstration using theatrical blood.

Rea was convicted, but evidence emerged soon after that she and her son had been the victims of a notorious serial killer named Tommy Lynn Sells. Sells was already facing execution in Texas for a nearly identical murder of a young Texas girl when he admitted to Illinois investigators that he had killed Joel as well.

This admission garnered Rea a retrial in 2006. Though the prosecution doubled-down on using Englert and his interpretation of the evidence, forensic consultant Kenneth Moses made detailed challenges of Englert’s methods and conclusions, ultimately stating “[t]here is no scientific basis for making such a claim.”

Rea was acquitted and later formally exonerated. Though she received a mere $87,057 in compensation for her imprisonment, that is nothing compared to the suffering caused by Englert’s scientifically unsupported testimony.

Englert’sBPA-related failures should have been apparent in David Camm’s case as well. Englert’s interpretation of the eight flecks of blood on Camm’s t-shirt as high-velocity backspatter drove the narrative that Camm murdered his family. This erroneous claim was unsupportable by the evidence, but it caused investigators to misinterpret or overlook real evidence pointing to the actual culprit.

A few months before Camm’s wife and children were murdered, Charles “Backbone” Boney was released from prison. Also known as “The Shoe Bandit,” Boney was known for holding women at gunpoint while stealing their shoes to satisfy his foot fetish.

Though Boney was questioned by investigators and initially denied meeting David Camm at the church that night, he later spun a story in which he sold a gun to Camm, allegedly wrapped in his prison sweatshirt.

However, the sleeve of this sweatshirt—which was found at the scene and had the moniker “BACKBONE” written on the inside collar—tested positive for Kim Camm’s saliva, which meant that Boney had held Rea hostage during their encounter. Also, Boney’s palm print was found on the passenger door of Kim’s Ford Brocno, where he placed his hand to brace himself while leaning into the vehicle to shoot Camm’s children.

At his third retrial in October 2013, the jury heard the full story regarding evidence of Boney’s involvement in the case, including the deal he made with investigators to testify against David Camm. They also heard testimony of forensic experts with more scientific training than Englert, who certified that the eight flecks of blood were so small that no reasonable conclusion could be based on their pattern.

“People see what they want to see,” opined Camm’s lead attorney, Richard Kamman, at his third retrial, about BPA. “It’s as accurate as a Ouija board.” Put another way, BPA appears to be forensic science’s equivalent to the Rorschach test, except people’s lives literally hang in the balance of what various BPA “experts” claim to see in the blood spatter.

Getting to Objective, Repeatable, and Reliable

Even a cursory review of how investigations and lives are derailed by unscientific forensics can leave a person with a sense of dread, especially considering there are likely hundreds, if not thousands, of innocent people who have been sentenced to decades in prison or possibly the death penalty.

It is worth noting that there have been some developments in relation to BPA that may make a small dent in the number of flawed prosecutions going forward.

The DOJ, through the NIJ, has spent $175 million between 2009 and 2017 on forensic research.One research group involving Daniel Attinger, a fluid dynamics specialist at Columbia University in New York, has received over $1.3 million in grants to study blood spatter. He previously studied how minor variations in fluids—such as between Coke and Diet Coke—can alter fluid stains. But blood is the “most complex fluid” he’s ever studied, Attinger said.

Some of this work to-date has involved improved analysis of how gravity affects blood in flight, which showed that previous BPA techniques to calculate the locations of victims contained untested assumptions about this effect.

A team at the University of Illinois in Chicago—including researcher Patrick Comiskey who has collaborated with Attinger—showed that blood is different from other fluids in that it becomes runnier as more force is applied to it, whereas most other fluids flow at the same rate regardless of the force applied. According to a PBS report, the team has also shown how complex blood can be due to its composition: “It teems with living cells and active enzymes, and its properties shift under the influence of minute fluctuations in temperature, or the presence of drugs.”

The researchers have been constructing a model to reverse-engineer “the type of gun, the bullets used, [and] the locations of the people involved, each with a score of the algorithm’s confidence in its results.” This model is incredibly complex, and attempts to assess the variances caused even “by the gas that escapes the muzzle of a gun after it’s fired.”

Attinger and Comiskey have stated their goal is to create a tool or app that investigators can use to reconstruct crime scenes based on blood evidence—including confidence scores in the results—all without investigators understanding the science behind it. However, because of the damage that such tools could wreak in the hands of overconfident experts who don’t understand their own limitations, others have warned about using novel techniques without rigorous validation.

“Forensic Science should be treated like any other consumer product,” M. Chris Fabricant, director of strategic litigation at the Innocence Project in New York City, said. “Before it’s allowed to be used on human beings, it should be scientifically tested and clinically demonstrated to be reliable, just like toothpaste”

Other researchers like Marilyn Miller, a forensics expert at Virginia Commonwealth University, are skeptical that tools, like the algorithm being tested by Attinger and Comiskey, could ever be accurate enough to be used in court. Perfect experimental conditions manufactured in a research lab are a far cry from the “highly textured, highly interrupted world of a crime scene,” she said to PBS

Miller is concerned that even if such tools are made available, “experts” in BPA may use them in court with more certainty than is warranted, especially when they haven’t been trained to understand research papers that are published, which impact their assessments.

Suzanne Bell, a forensics expert at West Virginia University, believes the broader issue relates to communicating the limitations of the evidence and the underlying science, rather than a willful ignorance.

“The problem isn’t that labs don’t want to do better,” Bell said. “It’s a resource issue: So much is demanded of [the personnel in forensics laboratories], who are busy doing cases... every minute they give to training, learning, and digesting this research takes away from casework.”

While resources may be an issue in accredited forensics labs, the issue with individual BPA experts—those certified in 40-hour workshops—is a combination of greed and willful scientific illiteracy among the analysts—and sometimes among the judges who allow them to testify.

Pamela Collof, a journalist reporting jointly for The New York Times Magazine and ProPublica, attended a 40-hour BPA workshop hosted in Yukon, Oklahoma, by the company founded by Tom Bevel and Ross Gardner. She describes days spent “[l]umbering around the garage in the biohazard gear we were provided—hooded Tyvek coveralls, latex gloves, safety goggles and masks secured with duct tape—[trying] to classify each bloodstain according to a dizzying taxonomy of spatters, drips, spurts, swipes and smears”

When the instructor began teaching how to trace the trajectory of blood to its source, he showed how a scientific foundation is dismissed in such trainings: “We’re not really going to focus on the math and physics; it just kind of bogs things down. I’ll teach you which keys on your calculator to press.”

The instructor also coached students on how to avoid difficult questions when called to testify in court on their analysis of evidence, saying they should avoid the word “probably” during testimony—a word which would give the opposing attorney an opening to ask questions about the reliability of the analysis: “You’ll be asked: ‘How probably? Eighty-five percent? Seventy-five percent?’ And you can’t say. It’s better just to say ‘the best explanation is...’”

This alarming disregard for scientific competency and accountability, along with several high-profile cases such as that of Joe Bryan, has prompted the Texas Forensic Science Commission to require changes in how BPA evidence is presented in Texas courts.

The Commission, created by the Texas legislature in 2005, is composed of seven scientists, one defense attorney, and one prosecutor. Their job is to assess the reliability and integrity of forensic sciences and then make recommendations to ensure that criminal convictions based on this evidence are sound.

The Commission held a hearing on BPA on January 22, 2018 and it invited leading forensic lab scientists, leading BPA analysts, and representatives from law enforcement. Some police officers who were also BPA analysts mocked the idea that college degrees made any difference in the reliability of BPA testimony. One remarked that “Thomas Edison was self-taught,” and another said of college degrees in science: “It means I can show up for a class, it means I can take a test and it means I can graduate.”

Tom Bevel—who makes money by certifying such police investigators as BPA experts—declined to attend the hearing but submitted a written statement to the commission recommending that analysts take more 40-hour classes, specifically two introductory and two advanced courses with different instructors.

Law enforcement’s resistance to higher standards for experts appeared to frustrate even the lone prosecutor on the Commission, Jarvis Parson, who exclaimed, “[w]e are talking about the liberty of individuals.”

And while researchers like Attinger have sought to make crime scene reconstruction more available, the Commission’s review stressed the dangers of continuing to allow experts without sufficient scientific expertise to testify in Texas courts. The final report stipulated that a bloodstain-pattern-based analysis must be performed by an accredited organization if it is to be allowed in court. Such accreditation is a labor-intensive process often too cumbersome for individual experts or even small firms and is more often appropriate for dedicated labs that employ well-trained scientists and technicians.

The Commission also mandated that analysts regularly undergo proficiency testing. Further, “[t]heir cases will be reviewed, and there will be an outside audit of their work each year. Their testimony will be monitored to ensure they aren’t overstating their findings in court”

Though the Commission’s decision only affects Texas courts, other courts look to large states like Texas and may adopt similar rules in response to the Commission’s decision. But there is no guarantee that this kind of accountability for bloodstain-pattern analysts will be replicated everywhere BPA is admitted into courts.

“If we don’t have technologies that are objective, repeatable and reliable, then we have no idea how many times we’re making the wrong decision,” according to Alicia Carriquiry, director of the Center for Statistics and Applications in Forensic Evidence, a government-funded project to measure the limits of forensic methods. “We don’t even have a way to estimate how many times we’re making the wrong decisions.”

Anthony Accurso is incarcerated at a federal prison in Seagoville, Texas. He was born in Kansas City, Missouri. Prior to incarceration, he ran his own tech consulting company, Accurso Technologies. He is a paralegal. He is a consultant with Reset Missouri, a re-entry project. He is working towards a future where prisons don’t exist, and people are not put on lists of ignominy.

Sources: propublica.org, ncjrs.gov, crime-scene-investigator.net, nycriminaldefenders.com, pbs.org, news-leader.com, blog.expertpages.com, reason.com, washingtonpost.com, signalscv.com, thenextweb.com, nytimes.com, buting.com, nbcnews.com, texasobserver.org, investigatinginnocence.org, tampabay.com, davisvanguard.org, theadvocate.com, deathpenaltyinfo.org, expertinstitute.com, wcojp.org, metro.us, thedailybeast.com, lawofficer.com, rrcc.edu

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