NEW ORLEANS — In a decades-old episode of “Columbo,” the deceptively bumbling detective holds up a piece of chewing gum discarded by a suspect and a piece of cheese found at a murder scene.

Wearing his trademark rumpled raincoat, he shows them to the puzzled suspect, telling him that the same teeth had bitten into each. “This is getting to be a big thing — bite-mark evidence,” explained Columbo, played by Peter Falk.

“I haven’t taken a mold of your teeth yet,” the detective said, but he promised, “When I do, it’s going to be the same thing as a fingerprint.” As the show ended, Columbo announced, “You’re under arrest, sir, suspicion of murder.”

Fast-forward to 2017, and forensic experts widely agree that identification of an individual by bite mark is risky business — and, according to many bite-mark experts, is invalid if the bite is in human skin.

Forensic bite-mark analysis first gained widespread attention in the 1978 prosecution of serial killer Ted Bundy and was quite the rage for years, as evidenced by the 1990 “Columbo” episode “Agenda for Murder.”

And then there is the case of Keith Allen Harward, an innocent man convicted of a 1982 rape and murder in Newport News in large part on the testimony of forensic dentists. His was dubbed “the bite-mark case.” Last year, after maintaining his innocence during the 33 years he spent incarcerated, Harward was cleared by DNA and released from prison.

With Hollywood’s current unrealistic portrayals of forensic science in such shows as “CSI,” the danger of bad science in courtrooms and its effect on judges and jurors remain despite a growing number of scientific studies and DNA exonerations that have raised red flags about some forensic disciplines.

At a workshop of the American Academy of Forensic Sciences’ annual meeting in New Orleans last week, forensic dentists, lawyers, judges and others, including Harward himself, outlined the shortcomings of forensic bite-mark analysis and hair microscopy and said problems extend into other forensic disciplines.

Betty Layne DesPortes, a Richmond defense attorney and the newly elected president of the 6,700-member AAFS, did not attend the workshop but said in an interview Thursday, “The academy has always been a forum for scientific advancement. Our meetings will continue to be a place for open and frank discussions of both the capabilities and the limitations of scientific techniques.”

DesPortes, who holds a master’s degree in forensic science, is familiar with the Harward case.

“We hope the legal system will recognize, as continued research has demonstrated, that bite-mark analysis should not be used for identification,” she said.

According to the Innocence Project, there are at least two pending capital murder cases, one in Pennsylvania and another in Louisiana, at which prosecutors hope to use biter-identification evidence, something even the American Board of Forensic Odontology no longer sanctions.

Independent studies and DNA exonerations in recent years have faulted the assumptions underlying bite-mark analyses, discredited the overstated testimony of hair examiners and raised questions about other forensic science disciplines. The problem is recognized by a growing number of forensic scientists and defense attorneys but less so by the courts.

Used properly, forensic science is an essential, effective law enforcement tool. A critical report from the National Research Council of the National Academy of Sciences in 2009 began by noting that for decades, forensic science disciplines have led to the conviction of criminals and the exoneration of innocent people.

But the 350-page NAS report pointed out that “in some cases, substantive information and testimony based on faulty forensic science analyses may have contributed to wrongful convictions of innocent people.

“This fact has demonstrated the potential danger of giving undue weight to evidence and testimony derived from imperfect testing and analysis. Moreover, imprecise or exaggerated expert testimony has sometimes contributed to the admission of erroneous or misleading evidence,” the report says.

In addition to bite marks, other forensic disciplines with limited or nonexistent empirical data supporting them — and that require interpretation by experts who are subject to conscious or unconscious bias — are areas of concern. They include firearm examinations, tire and shoe impressions, handwriting and fingerprints.


Harward’s was the bite-mark case featured at the New Orleans workshop last week, “Taking a Bite Out of Crime and Other Hairy Situations.” No fewer than six dentists were involved in Harward’s case, none of them disputing the conclusions of the two forensic dentists who testified against him.

The Innocence Project hopes his exoneration leads to a national review of old bite-mark cases comparable to one underway now by the FBI, the National Association of Criminal Defense Lawyers and others of old cases involving microscopic hair analysis, another forensic technique that has contributed to wrongful convictions.

In 1983, dental molds were taken from Harward’s teeth, compared with bite marks on the legs of a rape victim and used to convict the innocent man of a rape and murder. Harward is on his way to receiving some $1.6 million from the state for his wrongful imprisonment.

Since Harward’s case, numerous studies — including one performed by the ABFO — have undermined the two basic assumptions underlying bite-mark identification: that everyone has a unique set of teeth and that the uniqueness can be reliably transferred to human skin.

Odontologists also perform widely accepted, noncontroversial work such as identifying dead people from teeth. Controversy within the ABFO on comparing teeth with bite marks in criminal investigations was referenced by several speakers at the workshop.

Cynthia Brzozowski, a New York dentist and ABFO member, said the reason bite-mark analysis is so contentious is because, “It relies heavily on human judgment, it is prone to human error and cognitive bias, and we have no scientific studies to validate accuracy or reliability (or) to define the limits of our discipline.”

“We have no proficiency exam for bite-mark analysts,” she complained. She said many of the 28 wrongful convictions and charges caused by erroneous bite-mark comparisons involved experienced ABFO members, some of them past presidents of the ABFO and past presidents of the AAFS.

The ABFO recently changed its standards and no longer sanctions biter-specific testimony, but allows for odontologists to conclude if a suspect is excluded as a biter, cannot be excluded or that there was insufficient information to reach such a conclusion.

The Innocence Project argues that until there is a scientific basis for bite-mark evidence, all of it should be barred from courtrooms.


To date, no court has rejected bite-mark evidence, and many prosecutors believe that when the results are not overstated and put in proper context, bite-mark analysis is valid evidence.

The newly elected president of the ABFO, Paula Brumit, a Texas dentist, was in New Orleans last week and could not be reached for comment.

Adam Freeman, the immediate past president of the ABFO, told the Richmond Times-Dispatch last year that “The Innocence Project would essentially like us to say, ‘Well, that’s a bite mark so let’s not do anything.’ And that, to me, is not acceptable. What we need to do is put that evidence in the proper context.”

Chris Fabricant, one of the Innocence Project lawyers who represented Harward, counters that Harward’s case, in which a Navy dentist initially excluded Harward and then later changed his mind, proves experts can no more reliably exclude anyone on the basis of bite marks than there is for them to identify someone.

Anthony R. Cardoza, a California dentist and ABFO member, agrees. “If we’re going to continue in bite marks, we need studies to validate it. OK? We need reliability studies. We need studies for ... whether you can exclude or not exclude,” he told the workshop attendees.

The Texas Forensic Science Commission has recommended a suspension of bite-mark evidence in Texas.

Lynn Garcia, general counsel for the Texas commission, said the Innocence Project asked the commission to review the underlying science of bite-mark analysis and to determine appropriate limits for its use in light of a bite-mark case in Texas that led to a wrongful conviction.

She said a key piece of research that influenced the commission was a study done by the ABFO in which 38 members reviewed 100 photographs of skin injuries and were asked, among other things, if they could determine if it was a human bite mark. She said the results showed a significant spread of conclusions.

The lack of reliability concerned the commissioners, Garcia said.

“And I will tell you, frankly, what was probably most concerning was the fact that this data had not been published,” she said. “There were a lot of scientists on the commission, who felt in other disciplines, if there was data that was that significant of an alarming nature or not, it would have been out there by now.”

“This is the first time in the history of the forensic science commission, and maybe the only time, where the commission concluded that it should recommend to our court system in Texas, that there be a pause on the admission of bite-mark comparison evidence until the research can show better reliability and validity,” she said.

The commission also recommended rigorous proficiency testing of odontologists as is required in other forensic disciplines. A committee of prosecutors, defense lawyers and odontologists is now reviewing all other Texas bite-mark cases to make sure there are no other innocent people in prison as a result of bite marks.

“We’re not reviewing cases just to point out errors for the sake of it. We are truly on a search to make sure — or to try and identify — potential miscarriages of justice,” Garcia said.

Fabricant, who has been challenging bite-mark evidence in courts, has been urging odontologists across the country to review their old cases in light of the ABFO’s new standards but has thus far heard nothing.

Freeman, the former ABFO president, has strongly encouraged all members to review old cases and where opinions went too far to pursue corrections.

“I think we need to take responsibility for these miscarriages of justice our discipline has been a part of,” Freeman wrote in a statement on the ABFO website.


At last week’s workshop, speakers said the problem is not just with the forensic experts, but also a lack understanding by judges who admit flawed science or expert testimony in trials, lawyers who use it, and lawyers who do not challenge it.

The 2009 NAS reported concluded that, “The judicial system is encumbered by, among other things, judges and lawyers who generally lack the scientific expertise necessary to comprehend and evaluate forensic evidence in an informed manner, trial judges (sitting alone) who must decide evidentiary issues without the benefit of judicial colleagues and often with little time for extensive research and reflection.”

Fabricant and others at the workshop said few lawyers challenge bite-mark evidence and, when they do, it is still admitted. Such evidence was first admitted in a 1975 case in California that became a precedent for similar rulings in other states, he said.

“I can’t tell you how many experts that I have arguments with ... who tell me that their science is good because it’s admitted in court — that’s the validating instrument: some judge, some scientifically illiterate judge, let it in and so, therefore, it’s good science,” Fabricant complained.

Judge Pamela A.W. King of Minnesota, who was appointed to the National Commission on Forensic Science in 2014, told the workshop that, “There certainly are lots of judges who are going to take the position, ‘What do you mean we’re going to have (an admissibility) hearing about this? This has been around forever and there are all these opinions” that it is admissible.

“Trying to put that genie back in the bottle is really, really difficult,” she said.

King said, “This is not just about bite-mark cases, either. There are cases that are being prosecuted regularly ... in areas of evidence where they don’t have an appropriate (scientific) foundation.”

A big step forward, King said, would be “if we can get judges to even recognize that there’s a problem.” But she said lawyers need to raise questions about the validity of proposed forensic evidence so judges can hear concerns.

Another judge, Christopher J. Plourd of California, also spoke at the workshop. As a lawyer, Plourd represented a man wrongfully sentenced to death in Arizona on bite-mark testimony who was exonerated by DNA.

“Judges need to consider there has been a shift in the scientific community,” he said. “Judges are starting to ask questions. I think we’re sort of at the beginning of that educational process rather than at the end of it. At least the discussion is now occurring. ... No questions were seriously asked 10 or 15 years ago. It was just Gospel; everybody just accepted it.

“There are people in prison now on bite-mark cases that shouldn’t be there, and that’s the reality,” he added. “What’s happened with bite marks is really the same as a lot of other comparative disciplines, so we’re scratching the surface of an overall problem that exists in our system of justice,” Plourd said.

“It’s not going to go away,” he said.

Harward spoke at length at the conference, blasting forensic bite-mark evidence and urging that it never be used in a courtroom again.

“I’m not like y’all — I’m not doctors and scientists and lawyers and stuff — why even give it a shot?” he said. “Why even discuss it any more? Just do away with it.”

He also said he is still waiting for an apology from one of the dentists whose error sent him to prison.

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