Bite mark evidence used to be one of a new series of techniques that forensic experts used in criminal cases. It was hailed as a breakthrough.
However, in recent years more and more questions have been asked about this technique and it has become discredited.
In February this year, The Wall Street Journal reported on how a commission in Texas recommended that the state suspend the use of bite-mark evidence in criminal cases until more research is carried out.
The Texas Forensic Science Commission, an influential and important body, comprised of lawyers, scientists, law-enforcement authorities, was the first body of its kind to make a recommendation about a technique that is rapidly falling out of favor. It voted for a ban that would remain in effect until research could show bite mark evidence is reliable.
What is Bite Mark Evidence?
Bite mark evidence has been used for many decades. Because our teeth wear in a certain way, proponents of the technique maintain they form a unique pattern on a victim. Bite marks have been compared to fingerprints. The evidence also confirms the vicious nature of a crime.
The evidence can be traced to the case of Linda Peacock in Scotland in 1967.
The 15-year-old girl went missing from her home. Her body showed up at a cemetery covered in jagged bite marks.
Police obtained bite mark impressions from a number of suspects including Gordon Hay. His jagged teeth were so distinctive that investigators linked him to the crime. An expert profiled another 300 people, but Hay was convicted of the murder.
In recent years, bite mark evidence has come under serious scrutiny. Last year, Steven Mark Chaney, a Texan who was accused of killing a drug dealer and his wife because of bite mark evidence, had his conviction overturned, reported the Washington Post.
At the time of the trial, dentist, Jim Hales, said there was a one-in-a-million chance that the marks could have come from another person. The jury agreed and gave Chaney a life sentence in 1989.
In the intervening years, experts found there was little evidence to believe bite mark evidence is scientifically accurate.
Chris Fabricant of the Innocence Project, which worked behind the scenes on Chaney’s case, said bite mark evidence is “subjective speculation masquerading as science.”
The experts seem to agree, although their conclusions have come too late for inmates like Chaney who spent a quarter of a century behind bars based on flawed evidence.