Innocence Blog

Bite Mark Evidence Deemed Unreliable

Posted: June 14, 2013 12:21 pm

A recent Associated Press review of convictions based on bite mark evidence revealed that at least two dozen individuals had been exonerated, mostly as a result of DNA testing, after bite mark analysis contributed to their wrongful convictions. The investigation which included an examination of court records, archives, news reports and filings by the Innocence Project, found bite mark evidence to be unscientific and unreliable. 

Despite a lack of scientific proof that teeth can be matched to a bite in human skin, some forensic dentists still perform bite mark analyses for the prosecution in criminal trials, earning as much as $5,000 per case. The practice is not recognized by the American Dental Association or the FBI. If a New York City judge rules later this month that bite mark analysis cannot be admitted as evidence, it could be out of courtrooms for good, reported the Associated Press.


"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.

According to the Associated Press’ investigation, the first time a man was convicted based on bite mark evidence was in 1954 when a dentist testified a bite mark in a piece of cheese left behind in a grocery store that had been robbed matched the teeth of a drunken man found with 13 stolen silver dollars. In several high-profile cases, bite mark evidence appeared like cutting-edge science in the media. But by 2000, DNA evidence exonerated several men who had been convicted as a result of bite mark testimony that later proved unreliable.

Fabricant, of the Innocence Project, said what's most troubling about bite mark evidence is how powerful it can be for jurors.

"It's very inflammatory," he said. "What could be more grotesque than biting someone amid a murder or a rape hard enough to leave an injury? It's highly prejudicial, and its probative value is completely unknown."

Despite the overturned convictions and unreliable method, a forensic dentist has never been decertified and there has only been one member of the American Board of Forensic Odontology that was suspended. 

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Read about cases were bite mark evidence lead to wrongful convictions