Dr. L. Thomas Johnson

Potential Bite-Mark Database Causes Concern

May 15, 2008 03:22 PM
by Josh Katz
Researchers at Marquette University announced the creation of a computer program to decipher bite-mark characteristics, stoking debate about the admissibility of such evidence.

30-Second Summary

The researchers hope the new technology will be a step toward the formation of a bite-mark database, which would help authorities identify perpetrators in criminal cases.

Dr. L. Thomas Johnson and his team compiled 419 bite impressions from soldier volunteers in Wisconsin for the study. Johnson is planning to gather more samples throughout the country “to expand the database into something close to law enforcement's DNA databanks,” the Associated Press reports.

Bite marks have been used to convict suspected criminals for 40 years. In one of the most famous examples, serial killer Ted Bundy was found guilty of murdering a Florida State University student in 1978 after evidence linked his dental impression to bite marks on the victim’s body. 

However, critics say bite-mark testimony is unreliable, and the creation of a database would not change that. Dr. Mike Bowers, a deputy medical examiner in California, called Johnson’s study “scientifically illiterate."

The Innocence Project blames bite-mark testimony
on the false convictions of numerous individuals who were later exonerated by DNA evidence. The project cites a study indicating a “63.5% rate of false identifications.”

Opponents to such evidence argue that human skin can distort bite marks, teeth can change over time, and the matter can become highly subjective. But many agree that bite marks can be “helpful in excluding someone as a suspect, or determining that the suspect could be the one who inflicted the bite,” according to The New York Times.

Headline Link: ‘Scientists Are Building Database of Bite Marks’

Background: Controversial bite-mark testimony

Opinion & Analysis: ‘Cases Where DNA Revealed that Bite Mark Analysis Led to Wrongful Arrests and Convictions’


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