Category Archives: Research & Trends

hands show molar teeth over x-ray dental scan

Bite Mark Expert Witness Continues to Cause Controversy

Dr. Michael West, the forensic expert who was best known for his analysis of bite marks, continues to cause controversy with his techniques. Most recently, his work on a Mississippi murder trial has come under scrutiny.

West’s Background

West is a forensic dentist, originally from Hattiesburg, Mississippi. He became well known in the legal community as a teeth and bite mark analysis expert. He has also given testimony as an expert in crime-scene investigation, forensic photography, video enhancement, gunshot residue, wound patterns, bloodstain analysis, and the use of ultraviolet light for detecting evidence. Over a period of 15 years, West testified in 71 trials in 9 states.

West’s Critics

West has been criticized for overstating his findings and testifying on subjects where he had limited expertise. Following ethical investigations into his practices, he resigned from the International Association of Identification in 1993 and the American Academy of Forensic Sciences in 1994. West was investigated and suspended by the American Board of Forensic Odontology.

West has numerous critics. Dr. Richard Souviron, a Miami forensic dentist has stated, “His results are beyond outrageous…He has hurt a lot of people.” James Starrs, professor of law and forensic science at George Washington University, has stated, “He is clearly a sore on the body of forensic science…He is forever going beyond what other scientists are willing or able to say.” Robert Kirschner, former deputy chief medical examiner for Cook County, Illinois, says West’s “results shouldn’t be admitted in any court.” Kirschner claims that West’s work violates every rule of scientific inquiry and investigation and that West has never been able to document anything he claims to have done.

Despite the controversy over West’s practices, he continues to be used as an expert witness at trial.

Since 2000, at least 17 people who were previously convicted of murder or rape based upon bite mark testimony have been exonerated. West was the expert in two of those cases.

Bite Mark Analysis History

Bite mark analysis began in 1954 when a dentist testified that a bite mark in a piece of cheese, left behind in a grocery store that had been robbed, matched the teeth of a man who had been found with 13 stolen silver dollars. The man was convicted.

In 1974, two dentists testified that a man’s teeth matched a bite mark on a murder victim’s body. The defense attorney fought the admissibility of the testimony, but the court allowed it because of the 1954 testimony about the cheese.

Recent Controversy

Recently, West was deposed in the matter of Eddie Lee Howard v. State of Mississippi. Howard was convicted and sentenced to death for the rape and murder of an 84-year-old woman in 1994. Howard’s conviction was partially based upon West’s bite mark testimony.

Years later, Howard’s attorneys were able to have DNA testing on the knife that was allegedly used to kill the woman that Howard had been convicted of killing. The tests excluded Howard as the source of the male DNA on that knife. With this newly discovered evidence, Howard’s attorneys were able to reopen some issues in the case, including a challenge to West’s credibility.

At the deposition, West was questioned by Chris Fabricant, the Director of Strategic Litigation at the Innocence Project in New York. West was an uncooperative witness, failing to review his original trial testimony and maintaining that he stood by his 1992 testimony.

Howard is being represented by Vanessa Potkin, Peter Neufeld, and Dana Delger of the Innocence Project in New York.

cctv installed on the wall to property security

The Power of Video Evidence in the Court of Law

In Minnesota and Louisiana, video has played a key role in piecing together the details of two recent high-profile shootings involving white police officers and black residents. Footage taken by civilians captured both Philandro Castile’s and Alton Sterling’s last moments before their deaths, sparking outrage nation- and worldwide.

Why is video evidence so powerful? For one, it’s visually compelling, meaning it’s more likely to trigger an emotional response and potentially work in favor of the defendant. Secondly, it gives the jury more information to work with in addition to oral and written statements. For these reasons, visual evidence such as video has been shown to be advantageous to both lawyers and jurors in court. We’ll highlight some main types of video evidence and discuss what requirements must be met in order for video to be deemed admissible evidence in court.

Types of Video Evidence

There are many types of video evidence, but some notable examples include:

Body Cameras: In the past few years, the use of police body cameras has become more widespread (although a bill that called for their expansion in Colorado recently failed to pass in the state Senate).

While some say that body cameras are beneficial in holding police officers more accountable for their actions, the shooting of Alton Sterling in Baton Rouge, La., showed a flaw in this technology when the body cameras worn by the two officers involved became dislodged during the altercation with Sterling. Opponents of body cameras also argue that body cameras give the government more power to invade civilian privacy, especially since the ownership of footage caught on body cameras belongs to the police force. Therefore, the ability to release such footage to the public is subject to each police department’s own set of rules and local laws.

Dashboard Cameras: Similar to body cameras, dashboard cameras are placed on the dashboards of vehicles by either civilians or law enforcement. These types of cameras can be helpful in a variety of instances, especially in cases of DUI. For example, if a civilian is pulled over by an officer and subjected to an illegal search or excessive use of force, anything caught on camera can work in that person’s favor in court.

Like police body cameras, dashboard cameras come with their own set of drawbacks. Again, since dashboard cameras are the property of law enforcement, police are not necessarily required to release footage to the public. In the case of the shooting of Alton Sterling, the involved officers did have dashboard cameras, yet law enforcement has not yet released the footage that was captured at the time of this writing.

Surveillance Cameras: Surveillance cameras placed on public and private property can be instrumental in cases of theft, burglary, and violent crimes. In the case of the shooting of Alton Sterling, which took place outside of a convenience store, surveillance footage was captured but was confiscated by police.

Cell Phone and Similar Footage: These days, anyone can be a cameraman and use their cellphones and similar devices to record incidents as they occur. Cellphone footage has played a key role in telling the stories of both the Alton Sterling and Philandro Castile shootings, and if it weren’t for “citizen journalism,” we probably wouldn’t have as much information about the incidents.

When Philandro Castile was shot by an officer during a traffic stop, his girlfriend, Diamond Reynolds, who was in the car, began streaming the aftermath on Facebook Live. In the video, Reynolds recounts the series of events as she films Castile, who is slumped over in the driver’s seat and bleeding as a police officer points a gun through his window.

Similarly, civilian footage captured during the Alton Sterling shooting has established the timeline of events. Although surveillance and police video have not yet been released to the public, two videos taken by witnesses received massive media coverage and fueled conversations and protests about racism throughout the country.

Video in the Courtroom

As technology has become more widespread, so too has video and other forms of digital evidence. However, the admissibility of video has evidence has been met with some uncertainty due to its ability to be duplicated or easily manipulated.

Fortunately, U.S. courts have established their own criteria for viable digital evidence, which includes video:

  • The video must be authentic.
  • The video must be relevant.
  • The video must not be hearsay or must be admissible under an exception to the hearsay rule.
  • If there is an original copy of the video available, any copies or facsimiles will be held inadmissible in court.
  • The probative value of the video must outweigh any prejudicial effect.

In addition, the video must be properly stored by law enforcement in order to prevent tampering or damage.


There is no one-size-fits-all best type of video evidence. It’s important for any video captured via surveillance, body/dashboard cameras and cellphones to paint an accurate and well-rounded picture of the situation to ensure impartiality and hold the right individuals accountable for their actions.

Fingerprint Experts Question Fingerprint Science

Fingerprint Experts Question Fingerprint Science

Experts are often called upon to testify that a criminal defendant’s fingerprints match a fingerprint found at the crime scene. Combined with other evidence of a defendant’s guilt, a fingerprint can be convincing proof of criminal responsibility. But when a case hinges entirely upon the unexplained presence of a defendant’s fingerprint, guilt may depend on the presumption that no other person could have left that print.

The uniqueness of fingerprints is increasingly being called into question. Scholars disagree as to whether forensic fingerprint identification has been scientifically validated. As a practical matter, the only way to be certain that fingerprints are unique would be to compare the fingerprints of every person who has ever lived. That obviously can’t be done.

Even if fingerprints really are unique, the fallible nature of fingerprint identification is illustrated by the wrongful conviction of Stephen Cowens. After Cowens spent more than six years in prison, Boston police and prosecutors admitted they were mistaken when they said that fingerprints found at a murder scene “unquestionably” belonged to Cowens. Several other wrongful convictions have hinged on the testimony of fingerprint experts who made incorrect identifications.

The highly publicized arrest of Brandon Mayfield for terrorism was based on the FBI’s mistaken identification of a fingerprint. According to the FBI, it used “standard protocols and methodologies,” including verification by outside experts, to link the suspect’s print to Mayfield. The FBI eventually conceded its error, explaining that it relied on a digital image of the suspect’s print that was of “substandard quality” and that there were a “remarkable number of points of similarity” between Mayfield’s prints and the suspect print.

Questionable Identification Techniques

Forensic experts might be mistaken when making a fingerprint identification for a number of reasons. Fingerprints within families tend to be very similar. As people age, skin elasticity changes, which alters fingerprint impressions. Some skin conditions also affect fingerprints. Even two prints left by the same finger are never identical. Skin stretches. The angle at which the finger touches a surface, and the pressure exerted, will affect the fingerprint impression.

Prints recovered from a crime scene may be smudged or distorted. Sometimes only a partial print can be recovered, making identification problematic. Too often, the fingerprint analyst knows that the police suspect the guilt of a particular person, and that knowledge may instill an unconscious bias that blind testing (a key component of the scientific method) would remove.

Fingerprint examiners compare “points of similarity” between a fingerprint recovered from a crime scene (a “latent print”) and a suspect’s fingerprint. When the fingerprints are clearly dissimilar, the suspect should be excluded as the source of the print. When there are enough “points of similarity,” they typically testify that the suspect is the source of the latent print. In some cases, experts testify that the suspect is the only person in the universe who could have left the latent fingerprint.

Professor Simon Cole persuasively argues that the boundary between sufficient and insufficient “points of similarity” to make a definitive match has never been scientifically established. In an influential article, Cole examines 22 cases in which reputable fingerprint experts reached a “consensus judgment” that a latent print identification, relied upon as proof of guilt in a criminal case, was incorrect. In some of those cases, the defense used its own fingerprint expert to challenge the conclusion drawn by the prosecution’s expert. Some of the defendants were acquitted or their cases were dismissed, while others were wrongly convicted. In several cases, the prosecution’s expert testified that 12 to 14 points of similarity proved that the latent fingerprint belonged to the defendant.

Cole suggests that the 22 cases are “the tip of the iceberg.” He also suggests that the prevailing Daubert standard of expert evidence admissibility fails to act as a shield against unreliable fingerprint analysis because courts are insufficiently skeptical of claims that fingerprint identification is infallible.

How Should Fingerprint Experts Testify?

For many years, fingerprint experts testified that fingerprint identification is infallible. That view was supported by the FBI’s publication, The Science of Fingerprints: Classification and Uses. While fingerprint identification may be reliable in most cases, it is now clear that it is not infallible.

Simon Cole points out that experts have repeatedly testified that the “error rate” in fingerprint identification is zero. As the cases of Mayfield and Cowen (among others) demonstrate, that testimony is untrue. Cole also points out that fingerprint analysts have been encouraged to testify that the methodological error rate is zero while the practitioner error rate is unknowable but negligible. In other words, if identification methods are followed precisely, the error rate is zero, but there is no way to know how often analysts fail to follow the methodology.

Since the methodology does not exist in a vacuum but is always applied by a practitioner, Cole argues that any attempt to draw a distinction between the two error rates is specious. He suggests that ethical fingerprint analysts should never testify about a methodological error rate of zero, because that testimony is both meaningless and misleading.

In any event, many experts now agree that the “zero error rate” claim is not scientifically supportable. Since there is no way to be certain that every person has a unique set of fingerprints, even a perfect match, determined by state-of-the-art techniques, cannot be said with certainty to be error-free. In any event, the “zero error rate” claim is misleading because it invites the jury to believe in the mythical perfection of fingerprint science while deflecting attention from all the real-world factors that result in misidentifications.

Mike Silverman, the fingerprint expert who introduced an automated fingerprint detection system to London’s Metropolitan Police, thinks experts have a duty to make juries aware of the problems with fingerprint analysis. Silverman worries that jurors are influenced by shows like CSI. According to Silverman, the certainty that television viewers see on CSI “simply doesn’t exist” in the real world.

If a fingerprint expert determines that a latent print matches a suspect, it may be unlikely that the fingerprint belongs to anyone else. Silverman is careful to note that winning the lottery is also unlikely, but it happens. To assure that a defendant receives a fair trial, the fallibility of fingerprint identification is something that fingerprint experts should be willing to acknowledge.

Admitting the possibility of error (even if the possibility seems remote) does not detract from an expert’s credibility. Rather, it enhances credibility. Nobody’s perfect. Juries understand that, and juries are more likely to trust experts who acknowledge their own potential fallibility. A recognition that experts are advocates for the truth, not for a particular party, always makes an expert a better witness.

Lab Analysts May Be Required to Testify in Person in Criminal Trials

Discarded Evidence May Lead to Dismissal of a Murder Trial

Ronald Melnik has been in jail for over 5 years awaiting trial for the shooting death of Reza Payan at a 2011 Fort Lauderdale New Year’s party. Melnik was charged with second-degree murder. His defense attorney is now seeking dismissal of that charge based on evidence that has been destroyed.

Motion to Dismiss

In 2015, Melnik’s defense attorney, David Bogenschutz, wanted to independently test the sample of Payan’s blood because he did not trust the toxicology result. The report showed no foreign substances in Payan’s blood, but witness testimony indicated that Payan had consumed alcohol and marijuana that night. Bogenschutz also noticed a crime scene photo that showed a brass vial that later tested positive for ecstasy was located near Payan’s body.

When he found out that the sample had been discarded, he filed a motion to dismiss. In filing the motion to dismiss, Bogenschutz stated, “Respectfully, this is a constitutional blunder of enormous magnitude and far-reaching consequences.”

Bogenschutz was not the first to bring up the constitutional ramifications of discarding potential evidence. According to court filings, in January 2013, a now retired-Broward homicide prosecutor Brian Cavanagh emailed his colleagues that the new disposal policy “presents a significant ‘destruction of evidence’ problem when the defense wants to assert their right under the discovery rules to have a sample inspected and tested by their own expert.”

Standard Practice to Discard Evidence

At the Broward Medical Examiner’s Office, it is standard practice to discard specimens after one year. Officials say this is to save storage space and based on the limited shelf life of refrigerated specimens. This is also in accordance with the state’s administrative code.

The Broward County Medical Examiner who implemented this one-year standard, Dr. Craig Mallak, said that this is based upon state and national medical examiners’ guidelines. He said, “Even at a year, you’re really rolling the dice…This isn’t a static piece of evidence, this is biology.” Mallak is a physician and former Armed Forces medical examiner. He holds degrees in law and medicine from Creighton University and a bachelor of science degree from Michigan State University in criminalistics.

The Broward County Medical Examiner’s office has previously come under criticism for lack of accreditation from the National Association of Medical Examiners, demands placed on staff that detract from death investigations, and poor management of case evidence.

In the nearby Miami-Dade County, the standard policy is to keep bodily fluid toxicology samples for five years. The Palm Beach County Medical Examiner and treasurer of the Florida Association of Medical Examiners, Dr. Michael Bell, also keeps toxicology samples for five years in cases of homicide and undetermined death. However, Bell also states that the five-year period is “probably arbitrary” and not indicative of the quality of samples that are kept for long periods of time. Bell stated, “There may be drugs present that may be detected, but I think the concentrations are likely not to be accurate…Any interpretation beyond ‘yeah, those drugs are present,’ is probably going to be tenuous.”

Minnesota Considers Switch to Daubert Standard

Minnesota Considers Switch to Daubert Standard

The movement to require judges to follow the Daubert standard when they decide whether to admit expert testimony in a trial has met with success in a majority of states. The next state to make the change may be Minnesota. An advisory committee is considering whether the Minnesota Supreme Court should replace the state’s version of the Frye standard with the Daubert test. Whether the proposal will gain traction is unclear.

The Politics of Daubert

The push for the Daubert standard is often political. Insurance companies and businesses that manufacture or sell products usually believe that the Daubert standard favors defendants in civil suits. For that reason, they lobby state legislatures to adopt Daubert, a standard that is widely seen as giving judges greater authority to evaluate and reject unreliable expert testimony.

On the other hand, plaintiffs’ lawyers usually oppose the adoption of Daubert on the ground that it favors the interests of businesses over those of victims. Missouri’s governor recently vetoed the state’s legislative adoption of Daubert because (in his view) the standard hurts injury victims by increasing the cost of litigation.

In some states, the legislature’s decision to enact a Daubert rule does not assure that courts will embrace the rule. For example, the Florida legislature enacted a Daubert standard, but the Florida Supreme Court may decide that the authority to change the state’s rules of evidence is vested in the state judiciary, not the legislature. The court will soon decide whether to accept or reject the legislature’s Daubert rule.

Unlike Missouri and Florida, the impetus to change the rule in Minnesota is coming from a rules committee, not from state lawmakers. Minnesota’s rules of evidence are generally fashioned by the state’s supreme court. The court has noted that is has “primary responsibility under the separation of powers doctrine” to create rules of evidence, while recognizing an obligation to follow “reasonable” rules of evidence enacted by the state legislature.

To Change or Not to Change?

Until 1980, Minnesota relied on the Frye test of admissibility. The court admitted expert testimony if it was based on a scientific technique that was generally accepted in the relevant scientific community. Minnesota modified that test in 1980 by adding the requirement that expert testimony, to be admissible, must have a scientifically reliable foundation. Minnesota’s modified test has come to be known as the Frye-Mack standard.

The Minnesota Supreme Court’s Advisory Committee on the Rules of Evidence is studying a proposal to replace the Frye-Mack standard with the Daubert standard. The committee’s chair commented that the committee has “a general sense that there is dissatisfaction with Frye-Mack among Minnesota judges and lawyers.” At the same time, the chair made clear that he was speaking for himself, not for the committee.

Dissatisfaction with Frye-Mack is probably strongest among lawyers who represent the business community, just as dissatisfaction with Daubert tends to be strongest among lawyers who represent plaintiffs. In a large majority of cases, the standard makes no difference, since most expert testimony is likely to be admitted under either standard. In cases where expert evidence is more controversial, however, the more restrictive Daubert standard usually favors defendants over plaintiffs, since plaintiffs must often rely on expert testimony to meet their burden of proof.

Given that dynamic, it isn’t surprising to read in Minnesota Lawyer that “most in the plaintiffs’ bar wants the Minnesota courts to stick with Frye-Mack, while the defense bar would welcome a switch to Daubert.” Whether judges are also divided is unknown, but retired Minnesota Supreme Court Justice Paul Anderson told Minnesota Lawyer that Frye-Mack is a workable standard that is supported by a consistent and well-established body of precedent. Judges may support the Frye-Mack standard simply because they are familiar with it.

On the other hand, Justice Anderson observed, the Daubert standard has been the subject of varied interpretations in state and federal courts. Some courts emphasize that Daubert liberalized the admissibility of expert testimony, while Daubert’s detractors insist that the standard encourages judges to usurp the role of jurors in deciding whether expert opinions have merit. Justice Anderson asks “Why should we force our attorneys to read the entrails of multiple, conflicting opinions from across the country to try to figure out a new standard?”

What Will Minnesota Do?

Whether the advisory committee will recommend a change is far from a foregone conclusion. The committee expects to solicit public comment in the coming months. As the issue makes its way onto the radar of Minnesota’s litigators, the committee will need to sift through a variety of conflicting opinions.

Regardless of the advisory committee’s recommendation, the Minnesota Supreme Court might not be inclined to change the current rule. The court unanimously rejected Daubert (and reaffirmed Frye-Mack) in a 2000 decision that questioned whether judges are any more capable than juries of resolving disagreements among experts about the reliability of an expert’s methodology. The court also observed that federal courts have failed to apply Daubert uniformly and that its adoption in Minnesota would upset a settled rule that produces consistent results. Even if the advisory committee recommends adopting Daubert, the court might decide that no changes have occurred since 2000 that would warrant a significant revision of Minnesota law.

Wooden Mallet and flag Of New Jersey

Treating Physician Not Required to Prepare Expert Report in New Jersey

The rules of evidence in most jurisdictions require a party who wants to call an expert witness to notify the other party of the expert’s name. The rules may also require advance disclosure of the expert’s qualifications, opinions, prior testimony, and publications. In many jurisdictions, the expert must state his or her opinions in a written report that is disclosed to adverse parties prior to trial.

Jurisdictions that require an expert to prepare a report often make an exception for treating physicians who will only be asked to testify about their diagnosis and the treatment they rendered to a patient. In those cases, medical records serve as an adequate substitute for a report. In addition, treating physicians are different from retained experts, who usually expect to write a report. Treating physicians are busy with their patients and often balk at being asked to prepare a report that merely reiterates information contained in medical records.

New Jersey’s discovery rules permit a party to ask an opposing party to produce a report prepared by that party’s expert. The report must include a complete statement of the expert’s opinions and the basis for those opinions, including the facts and data upon which the expert relied. The rules make no explicit exception for treating physicians.

The New Jersey Supreme Court was recently asked whether a plaintiff who sued for disability discrimination was required to produce an expert report when she relied on the testimony of her treating physician to establish that she had a disability. The trial court excluded the treating physician’s testimony because no report had been prepared for pretrial disclosure. The supreme court concluded that the treating physician’s proposed testimony about his patient’s disability did not trigger the obligation to write a report.

Facts of the Case

Patricia Delvecchio was employed by the Township of Bridgewater as a police dispatcher. Dispatchers generally work three shifts on a rotating basis.

Delvecchio suffered from inflammatory bowel syndrome (IBS), a condition that worsened when she worked the midnight shift. Delvecchio notified the Township that she suffered from IBS and asked for an accommodation of her condition by assigning her to morning or afternoon shifts. She supported that request with notes from her gastroenterologist. The notes stated that Delvecchio’s IBS symptoms were under control when she worked regular daytime hours, but were exacerbated by assignments to the midnight shift.

After one year of assigning Delvecchio to the afternoon shift, the Township decided it was too burdensome to other dispatchers to relieve Delvecchio of all midnight shift assignments. The other dispatchers, however, cooperated in allowing Delvecchio to work daytime shifts. After additional intervention by Delvecchio’s gastroenterologist, the Township told Delvecchio that it would assign her to afternoon shifts when they were available, but insisted that she work occasional midnight shifts. It did so despite the gastroenterologist’s insistence that it was medically necessary for Delvecchio to avoid the midnight shift.

After Delvecchio repeatedly declined assignments to the midnight shift, the Township asked her to resign. When she refused, the Township made her a records clerk and reduced her pay. It later terminated her employment, citing excessive absenteeism.

Delvecchio’s Lawsuit

Delvecchio sued the Township, alleging that it violated New Jersey’s Law Against Discrimination by repeatedly assigning her to the midnight shift. Delveccio contended that IBS constitutes a disability under New Jersey law and that the Township had a duty to accommodate that condition by changing her work schedule.

Pursuant to New Jersey’s discovery rules, Delvecchio disclosed that her treating gastroenterologist would testify that Delvecchio had been diagnosed with IBS and that he wrote notes to the Township explaining that condition and the need for a work schedule change. However, Delvecchio produced no report from the gastroenterologist.

The judge ruled that New Jersey law does not allow a treating physician to testify about a plaintiff’s diagnosis or the impact of a plaintiff’s work schedule on her condition unless the physician has been designated as an expert witness. The judge allowed the gastroenterologist to testify that he was treating Delvecchio for IBS, but would not allow the doctor to explain IBS to the jury.

The court admitted the gastroenterologist’s notes into evidence but instructed the jury that they were received as evidence that Delvecchio requested an accommodation, not as evidence that she suffered from a disability. Having heard no physician’s testimony in support of the claim that Delvecchio was disabled, the jury found in favor of the Township. Delvecchio appealed.

Supreme Court’s Decision

New Jersey’s law against disability discrimination prohibits employers from discriminating against an employee with a disability “unless the nature and extent of the disability reasonably precludes the performance of the particular employment.” A disability under New Jersey law includes an infirmity that prevents “the normal exercise of any bodily function.”

A threshold question in a disability discrimination case is whether the employee is disabled. On appeal, the Township argued that evidence of a disability must be based on “a retained expert witness,” not on testimony from a treating physician.

The Township relied upon an earlier case in which the New Jersey Supreme Court held that “expert medical evidence” is required to prove the existence of a disability unless the disability is apparent. Seizing on the word “expert,” the Township argued that Delvecchio failed to designate her treating physician as an expert and failed to produce the report that New Jersey law requires experts to prepare. The Township claimed that a treating physician who is not retained as an expert cannot testify that a patient is disabled.

The supreme court disagreed. The court relied on a line of New Jersey cases that allow treating physicians “to offer medical testimony regarding the diagnosis and treatment of their patients” as a lay witness. Those cases regard treating physicians as giving testimony about medical facts, not medical opinions.

Recognizing that the attempt to distinguish a medical fact from a medical opinion creates “an artificial distinction,” the court ruled that treating physicians may always give relevant testimony about a patient’s diagnosis and treatment, even if that testimony might be characterized as an expert opinion. If the doctor’s opinion testimony extends beyond diagnosis and treatment, however, the doctor must be designated as an expert and must furnish a report before the testimony will be admissible.

The supreme court ruled that the trial court should have allowed the gastroenterologist to testify about Delvecchio’s “IBS diagnosis, the impact of IBS on [her] everyday life, and the steps that [he] recommended to alleviate [her] symptoms.” Since there was no suggestion that Delvecchio’s attorney intended to ask the doctor “to opine on global questions beyond the scope of his role as plaintiff’s treating physician,” Delvecchio was not required to designate the gastroenterologist as an expert. The court accordingly granted Delvecchio a new trial.

California Law Legal System Concept

California Mental Health Experts Given Greater Latitude to Testify About a Defendant’s Mental State

A landmark decision by the California Court of Appeal in May 2016 gives mental health experts a greater role in the defense of criminal charges. The Herrera decision is already being cited as a basis for granting new trials to defendants who claim that judges improperly limited the testimony of their expert witnesses.

Evidence at the Herrera trial

Richard Arce Herrera was convicted of first degree murder. A witness testified that she saw Herrera stop his car in the street and chase someone who fled from the vehicle. Another witness later saw Herrera kneeling over the victim on the ground next to a car. Herrera appeared to be performing CPR. That witness saw Herrera enter his car and drive away.

The victim had been stabbed 21 times. He had shallow stab wounds in his back and deeper wounds in his chest and abdomen. He died from blood loss.

When Herrera arrived at his home, he appeared to be in shock. He told his parents that he had killed someone in self-defense after being attacked and raped. He showed his parents an injury on his side. His parents called 911.

Over a period of three years, beginning at the age of eight, Herrera was molested repeatedly. He was raped at the age of 15 and again at the age of 19. He became suicidal and obtained counseling to help him cope with his stress.

The murder victim was a childhood friend of Herrera’s. Herrera met him at a bar. The victim later began to touch Herrera inappropriately. Herrera testified that the behavior triggered flashbacks and caused him to have a panic attack.

Herrera agreed to drive the victim home because the victim was intoxicated. The victim began to touch Herrera again, then struck Herrera when Herrera rejected his advances. Herrera had a steak knife in the car’s console. He testified that the victim grabbed the knife and lunged at him, grazing his abdomen. A prosecution witness testified that Herrera had a circular abrasion on his abdomen that was not consistent with a knife wound.

Herrera testified that he took the knife from the victim after a struggle. Herrera said he began reliving the past and responded by stabbing the victim. After the victim jumped from the car, Herrera chased him. When he caught up with the victim, Herrera stabbed him repeatedly. In his mind he was stabbing all the people who had molested or raped him.

Herrera came out of his rage and took the victim back to his car, intending to drive him to a hospital. However, he could not lift the victim into his car. He then tried to perform CPR. Realizing that the victim was dead, he drove to his parents’ home.

Expert Testimony

During his trial, Herrera called two mental health experts as witnesses. Herrera’s psychiatrist testified that Herrera had suffered for some time from post-traumatic stress disorder (PTSD). Her last session with Herrera occurred two weeks before the killing.

The other expert’s testimony was critical to the appeal. Dr. Nancy Kaser-Boyd is a clinical and forensic psychologist. She evaluated Herrera after the killing. She confirmed that he suffers from PTSD. She also testified that the perception of a threat can trigger a “fight or flight” response in a person with PTSD. Under those circumstances, a traumatized person might enter a “peritraumatic dissociative state.” People in that state feel emotionally detached from their actions, as if they were watching someone else. That testimony was consistent with Herrera’s testimony about how he felt during the killing.

The trial court precluded Dr. Kaser-Boyd from testifying about Herrera’s mental state at the time of the offense. In particular, she was not allowed to testify that, at the time of the killing, Herrera was suffering from PTSD, that he was in a peritraumatic dissociative state, or that he was psychiatrically impaired.

Herrera was convicted of first degree murder. He appealed, claiming that trial court violated his right to present evidence by restricting the testimony of his expert witness.

Mental Health Testimony and the Right to Present a Defence

Criminal defendants have a constitutional right to present relevant evidence that tends to establish their innocence. Herrera argued that the right to present Dr. Kaser-Boyd’s testimony trumped section 28 of the California Penal Code, which bars the admission of mental health evidence to show that a defendant did not have the capacity to form a mental state (such as intent, premeditation, or malice aforethought) that is required as an element of the charged offense.

Section 29 of the Penal Code states that the trier of fact (in this case, the jury) shall decide “whether the defendant had or did not have the required mental state.” California courts have held that these sections do not prevent a defendant from basing a defense on the absence of a required mental state, but preclude the defendant from introducing expert testimony to establish that defense. In other words, a defendant can testify “I didn’t intend to kill him” but cannot bolster that testimony with an expert opinion as to whether he actually formed the intent to kill.

The California rule is common. Similar rules have frequently been challenged as violating the right to present a defense, but those challenges have typically been unsuccessful. In Herrera’s case, the court of appeal did not hold that sections 28 or 29 are unconstitutional, but read them narrowly in order to maximize an expert witness’ latitude to testify about a defendant’s mental state at the moment an alleged crime was committed.

The Appellate Court’s Decision

The court decided that Dr. Kaser-Boyd should have been permitted to testify that Herrera was in a peritraumatic dissociative state and was suffering from PTSD at the time the offense was committed. While that testimony implies that Herrera did not form the intent to kill, the court concluded that the testimony was admissible, provided that Dr. Kaser-Boyd did not expressly opine that Herrera did not intend to kill the victim. Inferences about Herrera’s intent at the time of the killing were for the jury to draw, based on Dr. Kaser-Boyd’s opinions about Herrera’s mental status and on the other evidence.

If the jury had drawn the inference that Herrera’s peritraumatic dissociative state relieved him of responsibility for a premeditated killing, it might have found him guilty of a less serious offense, such as second-degree murder or voluntary manslaughter. It might also have concluded that Herrera acted in self-defense or in “imperfect self-defense,” if Herrera mistakenly believed that his life or security was imperiled. The court therefore reversed Herrera’s conviction and ordered that he be given a new trial with the benefit of full testimony from his expert witness.

Implications of the Herrera Decision

Appellate courts in many states (like many state legislatures) are skeptical of psychological evidence that supposedly “intrudes” upon the jury’s obligation to decide whether a defendant had the state of mind required for a crime. As brain science continues to advance, however, courts are likely to become more comfortable with expert testimony that explains how a defendant’s mental condition likely affected him at the time an alleged crime was committed.

The Herrera decision is already being cited in support of a motion for a new trial filed on behalf of a California woman who was convicted of murdering her husband. Her expert was precluded from testifying about how her husband’s constant abuse during a period of 29 years could have affected her perception of the threat that her husband posed to her on the night that she shot him. In that case and others, the Herrera decision may open the door for defendants to place greater reliance on expert testimony that helps juries understand their behavior.


Convictions Based Solely on “Touch DNA” May Be Unreliable

Fans of the CSI shows know that DNA is the gold standard of evidence in criminal investigations. Unless a criminal is wearing gloves and covered from head to toe in protective clothing, there is a good chance that the criminal will leave traces of DNA at the crime scene.

Crime scene investigators are taught that “every contact leaves a trace” of DNA, a principle that is attributed to Edmond Locard. The transfer of just a few skin cells may be enough to provide investigators with “touch DNA” that can be matched to a known suspect or to someone whose DNA appears in a database. Touching a doorknob or any other object may leave a trace that can be used to identify the culprit.

Given the power of “touch DNA” to unlock the mysteries of a crime scene, investigators often conclude that finding the DNA from someone who denies ever visiting the crime is proof of guilt. New studies, however, establish that DNA can be transferred to a crime scene even if the person to whom the DNA belongs has never been there. When that happens, DNA may point the finger of guilt at an innocent person.

The Risk of Inadvertent DNA Transfer

An article in Scientific American warns that police, prosecutors, and juries may be making a mistake when they treat the presence of DNA as infallible proof of guilt. The article spotlights the arrest of a homeless man who was charged with murdering a multimillionaire in Silicon Valley. The arrest was based solely on the discovery of the homeless man’s DNA at the crime scene. Since the man told the police he had never been there and could not explain the presence of his DNA, the police and prosecutors assumed he was the murderer.

The homeless man’s defense team soon found irrefutable evidence of their client’s innocence. The homeless man had been hospitalized before the murder. He was nearly comatose and under constant medical supervision when the crime was committed.

Further investigation revealed that paramedics responded to the crime scene hours after treating the homeless man. The paramedics touched the homeless man, then unwittingly transferred his DNA to the crime scene. If the homeless man did not have proof of his whereabouts during the commission of the crime, he would be facing a wrongful conviction.

A number of studies show how easy it is to transfer someone else’s DNA. If you shake hands with someone, that person’s DNA will probably be left on the next object you touch. If the next object you touch is later used as a murder weapon, an innocent person may become the prime suspect. Laundry workers who touch clothing, hotel maids who touch the trash that they empty from a bathroom wastebasket, and children who hug their parents may be transferring someone else’s DNA to objects they touch throughout the day.

Defenses to DNA evidence have traditionally been built upon the contamination, degradation, or mislabeling of samples; the failure to follow proper analytical protocols; and the use of expert statisticians to explain why the statistical probabilities of DNA matches are overstated by DNA experts. When it comes to “touch DNA,” a stronger defence — and a greater risk of a wrongful conviction — may be the possible transfer of a defendant’s DNA to a crime scene by a third party.

The Need for Caution in Forensic Science

The new revelation about DNA fallibility comes at a time when other forensic sciences are subject to increasing scrutiny. Courts are becoming increasingly skeptical of forensic scientists who present doubtful evidence as if it were based on irrefutable science.

Based solely on microscopic examination, crime lab analysists have often testified that a hair found at a crime scene came from a defendant, when an examination of the physical characteristics of hair can only support a conclusion that the hair is similar to the defendant’s hair. The FBI admitted in 2013 that the scientific “testimony used to convict thousands of individuals was scientifically invalid.” Earlier this year, a judge overturned a 1987 conviction because it was founded on unreliable hair evidence.

Bite mark evidence is even more suspect. The California Supreme Court recently granted William Richards a new trial on the ground that the bite mark expert who testified against him later admitted that his scientific methodology was unreliable. Richards’ conviction of murdering his wife was based on circumstantial evidence, including the expert’s opinion that Richards’ teeth matched a photograph of an alleged bite mark on wife’s hand. The new trial was granted only after California enacted a law permitting convictions to be overturned on the basis of an expert’s admission of error during the original trial.

The science of DNA is on firmer footing than bite mark or hair analysis, but expert witnesses who testify about DNA still need to exercise the caution that is the trademark of an honest scientist. The presence of trace DNA is circumstantial evidence, but in the absence of corroborating evidence it should not be seen as proof of guilt. The Scientific American article emphasizes that point by quoting the author of Inside the Cell: The Dark Side of Forensic DNA: “If you don’t bring in the appropriate amount of skepticism and restraint in using the method, there are going to be miscarriages of justice.”

hands show molar teeth over x-ray dental scan

Expert Bite-Mark Evidence Debated in Texas

Should bite-mark experts be permitted to testify in criminal trials? An editorial in the San Antonio Express-News suggested that “Texas prosecutors and judges should maintain the integrity of the criminal justice system by voluntarily declaring a moratorium on the use of bite-mark evidence.” Responding in an op-ed, a Texas judge contends that a moratorium “is no solution.”

The controversy echoes a debate among experts as to whether the identification of a suspect based on bite marks has any scientific validity. The Texas Forensic Science Commission recently joined that debate by advocating against the admission of expert bite-mark testimony in criminal trials.

Texas Forensic Science Commission

The Texas Forensic Science Commission is making a diligent effort to improve the state’s criminal justice system by assuring that expert witnesses who profess to base opinions on science actually have a scientific foundation for those opinions. The Commission recognizes that Texas judges have an unfortunate history of permitting expert witnesses to help prosecutors obtain unwarranted convictions by rendering opinions that are unsupported by a valid scientific methodology.

The Commission was created in response to revelations that the Houston Crime Lab regularly used shoddy analytic procedures and employed unqualified experts who told lies in court that contributed to the conviction of innocent defendants. The Commission is now viewed as a pioneer in the effort to prevent innocent defendants from being convicted on the basis of expert scientific opinions that are unsupported by modern science. In addition to bite-mark evidence, the Commission is scrutinizing the subjective opinions routinely offered by experts in hair identification and arson investigation.

At a meeting of the Commission’s Bite Mark Analysis Panel in February 2016, Dr. David Senn, a forensic odonatologist who champions bite-mark analysis, explained that “research relating to bite-mark analysis is slow going, but being developed.” At an earlier meeting, Dr. Senn told the panel that a “competent forensic dentist … can look at a bite and create a profile about what kind of teeth could’ve made it if there’s sufficient information in the bite mark.” The problem, Dr. Senn said, is that 85% to 90% of the injuries he reviews lack sufficient detail to be compared with a suspect’s teeth.

Other experts are skeptical of a dentist’s ability to match bite marks with teeth even under optimal conditions. As skin stretches or contracts, the relative position of marks on the skin changes. Some bite mark analysts have been tempted to move the skin on which bite marks are displayed until it matches a suspect’s teeth. Even when experts try to reach an objectively accurate result, studies show that bite-mark analysis has an error rate of up to 64%.

One study, using teeth held in place by a clamp to make bite marks on cadavers, found that no two bites produced the same marks. The researchers concluded that human skin does not reliably record the patterns of teeth and that the absence of consistent marks produced by the same set of teeth undermines the possibility of matching bite marks to suspects.

Another study questioned whether dentists are even capable of recognizing bite marks. Researchers showed 100 pictures of bite marks to 38 dentists who each had at least 20 years of experience. The dentists disagreed about whether 96 of the 100 pictures depicted bite marks.

Bite-Mark Evidence in Texas Courts

A member of the Forensic Science Commission who is also a professor at Texas A&M’s Baylor College of Dentistry observed that too many Texas judges rely on precedent rather than science to admit bite-mark evidence. The Commission’s general counsel agreed that scientific evidence should be admitted as proof of guilt only if it is based on sound science, not “just because the judge says it’s okay.”

The Bite Mark Analysis Panel recommended a moratorium on the use and admission of bite-mark evidence in Texas courts until acceptable scientific standards are created that will guide the expert opinions rendered by forensic dentists. While the editorial board of the San Antonio Express-News agreed with that suggestion, District Judge Robert Barton pointed out that judges have no power to issue moratoria. They apply rules of expert evidence admissibility on a case-by-case basis.

Texas follows its own version of the Daubert standard for the admission of expert testimony. Using that test, the state’s Court of Criminal Appeals upheld the introduction of bite-mark evidence in a 1990 decision. The wisdom of admitting bite-mark evidence as proof of guilt should give judges pause after Texas court found that unreliable bite-mark evidence formed the basis for one of the state’s most notorious wrongful convictions.

While Judge Barton expressed concern that the blanket exclusion of bite-mark evidence would be “arbitrary,” some might conclude that expert evidence with a 64% error rate is arbitrary, and that its exclusion is a safeguard against unjust convictions. Since expert testimony can have a profound impact on a jury, certain kinds of scientific evidence have consistently been deemed inadmissible for fear that juries might give the evidence undue weight. Polygraph evidence is a long-standing example.

While trial judges have no authority to impose a moratorium, Texas appellate courts have the authority to rule that bite-mark evidence is too unreliable to satisfy the state’s standard of admissibility. More importantly, legislatures can decide as a matter of policy that bite-mark evidence should be excluded as proof of guilt in criminal trials unless and until the legislature is convinced that it is supported by sound science.

Given the work of the Forensic Science Commission, it is difficult to believe that responsible judges would continue to permit the introduction of bite-mark evidence as proof of guilt in a criminal trial. Whether that possibility should be eliminated by the declaration of a moratorium is a question that the state legislature should seriously consider.

Neuroscientific Evidence in the Courtroom

Neuroscientific Evidence in the Courtroom

The increasing importance of neuroscientists as expert witnesses in death penalty hearings and other court proceedings is highlighted in a recent article in The Atlantic. The article calls attention to a Duke University study of more than 1,600 court decisions that addressed neuroscientific evidence between 2005 and 2012.

According to the Duke study, neuroscientists and related experts testify in about 5 percent of all murder trials and in 1 to 4 percent of all other felony trials. The experts are commonly used to provide mitigating evidence in an attempt to lesson a criminal defendant’s punishment, but neurobiological experts also testify regarding a defendant’s competency to stand trial or to plead guilty, as well as a defendant’s ability to give a voluntary confession when questioned by the police. Less frequently, they testify in support of insanity defenses and defenses based on a defendant’s inability to form the mental status (such as intentional conduct) required to commit the charged crime.

Neurobiology and the Law

The authors of the Duke study grouped neuroscience and behavioral genetics together under the umbrella of neurobiological evidence. The fields of neuroscience and behavioral genetics are increasingly linked as researchers discover that neither a purely genetic nor a purely neuroscientific approach are adequate to explain the biological components of human behavior. In fact, understanding the “pathways between gene, brain, and behavior” may require an interdisciplinary approach that “requires expertise in genetics, neuroscience, psychology, and psychiatry.”

Criminal defense lawyers are turning to neurobiological evidence to explain a client’s criminal behavior. One example links a gene known as MAOA (Monoamine Oxidase A) with antisocial behavior. The gist of the defense is that a criminal defendant should not be held responsible for behavior that results from biology rather than choice. Experts assist lawyers in presenting that defense through MAOA genotyping and neuroimaging.

The use of neurobiology in criminal defense has sparked debate among experts and non-experts alike. If people are truly not responsible for criminal behavior, why should they be punished for their conduct? Neurobiology arguably undermines the retributive foundation for the criminal justice system.

At the same time, prosecutors have used neurobiology to argue that the safety of society requires that criminals who have a genetic or neurologic propensity to behave violently should receive longer sentences. They have contended that the need to protect society trumps the question of personal responsibility for lawless behavior.

Debating Free Will

The debate about the role that neuroscience should play in criminal law falls within a larger scholarly debate about whether free will actually exists. Many neuroscientists conclude from experimental data that the subjective sense of free will is an illusion. They argue that behavior is determined by physical and biological laws, not by individual choice. If that is true, the deterrent value of criminal punishments may be nonexistent.

Scientific evidence notwithstanding, those conclusions are unpopular with a large majority of people who prefer to believe that they make rational or moral decisions about how to behave. The deterministic approach of neuroscience arguably undermines not only criminal law, but moral codes and a good bit of philosophy since the age of Aristotle. If people should not be held responsible for behavior that is not the product of free will, doesn’t that give bad people (or even good people) an excuse to misbehave?

The Future of Expert Testimony

While the authors of the Duke study found that attempts to introduce neurobiological testimony in criminal trials have been relatively unsuccessful, the study also found that attempts to introduce expert neurobiological evidence have been “more successful than most scholars believe.” At least with regard to some claims that criminal defendants raise, “testimony by an expert on the matter may serve as powerful evidence that impacts the outcome of the case for the defendant.”

While neurobiological evidence is used in the sentencing phase of capital cases, it is more often introduced to mitigate punishment in serious felonies that do not involve the death penalty. Since sentencing hearings take place after guilt has been determined, the rules of evidence governing the admission of expert testimony are often more relaxed than those that govern evidence during the guilt phase of a trial.

More controversial is whether to allow expert neurobiological testimony in an effort to persuade a jury that a defendant did not commit the charged offense. When, for example, a crime requires proof that a defendant acted intentionally, a neurobiologist might conclude that the defendant was incapable of forming the specific criminal intent that the law requires. To the extent that experts are allowed to render such opinions, juries commonly reject them.

Still, expert testimony from neuroscientists can make a difference. The Duke study, which defined neurobiological evidence broadly to include not just brain scan results and biomarker examinations but also the results of neuropsychological testing, found that the evidence makes a difference in 20 to 30 percent of cases in which it is admitted.

Measuring the impact of neuroscientific evidence is nevertheless difficult. A jury that acquits a defendant or decides not to impose the death penalty may have done so even in the absence of the expert evidence. Appellate courts have reversed convictions and remanded for new hearings or trials because neuroscientific evidence was improperly excluded (or because the defense attorney failed to present it), but the result after the new trial or hearing may turn out to be the same.

Given the gaps in knowledge about the connection between the brain, genetics, and criminal behavior, not all neuroscientists agree that expert neurobiological evidence should play a role in the courtroom. Notwithstanding that controversy, as scientific analysis becomes increasingly sophisticated, experts in neuroscience are likely to play a larger role as witnesses in criminal trials.