In 1987, Steven Mark Chaney was sentenced to life in prison. Chaney was accused of the stabbing death of a drug dealer. An expert testified that a bite mark on the victim’s arm matched Chaney’s bite print.
But 28 years later, Chaney was released from prison. He’s one of more than a dozen people around the country who have been released or exonerated in cases involving bite-mark testimony that was later debunked.
Now, the Texas Forensic Science Commission has recommended that bite mark evidence should no longer be admitted in court cases.
Tamara Tabo, a columnist for abovethelaw.com, runs the Center for Legal Pedagogy at the Texas Southern School of Law. She says what’s at play here is the lack of evidence that it works – Tabo says there have been no “significant scientific studies” to establish the validity of using bite marks to identify someone.
“There have been no peer-reviewed studies, no large population studies,” she says, “all the sorts of things that you would expect in order to establish that a forensic technique is going to be useful in a criminal trial.”
While the recommendation is just that – a recommendation and not a requirement – Tabo says it will likely change the way that trial judges handle cases.
“Trial judges have the job of ensuring that all of the scientific testimony or evidence that is admitted is not only relevant to the case at hand, but is also reliable,” she says. “So, trial judges will now be looking much more closely at any bite mark evidence that prosecutors might want to bring into a trial, and they’re much more likely to either significantly limit or completely exclude the use of bite marks in criminal cases.”
And it’s not just in Texas. Reconsidering the use of bite mark evidence will likely have far-reaching effects, Tabo says.
“There have been concerns nationwide and in fact even worldwide,” she says. “The UK, for example, has had similar controversies about using bite marks in criminal trials.”