At least 24 men convicted or charged with murder or rape based on bite marks on the flesh of victims have been exonerated since 2000, many after spending more than a decade in prison. Now a judge’s ruling later this month in New York could help end the practice for good.
A small, mostly ungoverned group of dentists carry out bite-mark analysis and their findings are often key evidence in prosecutions, even though there is no scientific proof that teeth can be matched definitively to a bite into human skin.
DNA has outstripped the usefulness of bite-mark analysis in many cases: The FBI doesn’t use it, and the American Dental Association does not recognize it.
“Bite-mark evidence is the poster child of unreliable forensic science,” said Chris Fabricant, director of strategic litigation at the New York-based Innocence Project, which helps wrongfully convicted inmates win freedom through DNA testing.
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Supporters of the method, which involves comparing the teeth of possible suspects to bite-mark patterns on victims, argue it has helped convict child murderers and other notorious criminals, including Pacific Northwest serial-killer Ted Bundy. They say problems that have arisen are not about the method but about the qualifications of those testifying.
“The problem lies in the analyst or the bias,” said Dr. Frank Wright, a forensic dentist in Cincinnati. “So if the analyst is … not properly trained or introduces bias into their exam, sure, it’s going to be polluted, just like any other scientific investigation. It doesn’t mean bite-mark evidence is bad.”
The Associated Press reviewed decades of court records, archives, news reports and filings by the Innocence Project to compile the most comprehensive count to date of those exonerated after being convicted or charged based on bite-mark evidence.
The AP analysis found that at least two dozen men had been exonerated since 2000, mostly as a result of DNA testing.
Two court cases this month are helping to bring the debate over the issue to a head. One involves a 63-year-old California man who is serving a life term for killing his wife, even though the forensic dentist who testified against him has reversed his opinion.
In the second, a New York City judge overseeing a murder case is expected to decide whether bite-mark analysis can be admitted as evidence, a ruling critics say could kick it out of courtrooms for good.
Bite-mark analysis hit the big time at Bundy’s 1979 Florida trial.
On the night Bundy went on a killing spree that left two young women dead and three others seriously wounded, he savagely bit one of the murder victims, Lisa Levy. A Florida forensic dentist, Dr. Richard Souviron, testified at Bundy’s murder trial that his unusual, mangled teeth were a match.
Bundy was found guilty and executed. The bite marks were considered the key piece of physical evidence against him.
That nationally televised case and dozens more in the 1980s and 1990s made bite- mark evidence look like infallible, cutting-edge science, and courtrooms accepted it with little debate.
Then came DNA testing. Beginning in the early 2000s, new evidence set free men serving prison time or awaiting the death penalty largely because of bite-mark testimony that later proved faulty.
At the core of critics’ arguments is that science hasn’t shown it’s possible to match a bite mark to a single person’s teeth or even that human skin can accurately record a bite mark.
Only about 100 forensic dentists are certified by the odontology board, and just a fraction are actively analyzing and comparing bite marks. Certification requires no proficiency tests. The board requires a dentist to have been the lead investigator and to have testified in one current bite-mark case and to analyze six past cases on file — a system criticized by defense attorneys because it requires testimony before certification.
Testifying can earn a forensic dentist $1,500 to $5,000 per case, though most testify in only a few a year. The consequences for being wrong are almost nonexistent. Many lawsuits against forensic dentists employed by counties and medical examiner’s offices have been thrown out because as government officials, they’re largely immune from liability.
An internal debate over the future of the practice was laid bare at a conference in Washington in February, when scores of dentists — many specializing in bite-mark analysis — attended days of lectures and panel discussions. The field’s harshest critics also were there.
Dr. Gregory Golden, a forensic dentist and president of the odontology board, acknowledged that flawed testimony has led to the “ruination of several innocent people’s lives” but said the field was entering a “new era” of accountability.
Souviron, who testified against Bundy in 1979 and is one of the founding fathers of bite-mark analysis in the U.S., argued there’s a “real need for bite marks in our criminal-justice system.”
In an interview, Souviron compared the testimony of well-trained bite- mark analysts to medical examiners testifying about a suspected cause of death.
“If someone’s got an unusual set of teeth, like the Bundy case, from the standpoint of throwing it out of court, that’s ridiculous,” he said.