Bite mark evidence should be inadmissible in the courtroom until researchers can establish basic criteria to measure its reliability, members of the Texas Forensic Science Commission said Thursday.
In a move that could resonate across courts nationwide, the state commission is expected to vote Friday on whether to recommend a temporary moratorium on the use of such evidence in criminal proceedings until further study is conducted. The panel doesn’t have the power to ban it altogether, but its decision is likely to influence judges and prosecutors in Texas, and it could have a ripple effect in other states.
“As it just now stands, it’s too subjective, and as a result, I am ready to face the absence of it in court,” said commission member Richard Alpert, a Tarrant County assistant district attorney.
Dr. Vincent DiMaio, former chief medical examiner for Dallas and Bexar counties, said there is a potential to allow such evidence in the courtroom in the future, but “I think at the present time, the bite mark examination doesn’t rise to the level of forensic discipline.”
Thursday’s discussion of bite mark evidence comes as the Texas Forensic Science Commission has become one of the nation’s most important forensic science policy groups. The commission is leading the review of hundreds of old cases in an effort to halt the prosecutions of innocent people based on outdated science, including inaccurate interpretations of DNA evidence. It has also launched an investigation into hair analysis.
Those who support using bite mark evidence in court, which has been allowed in the U.S. since 1975, contend the practice has helped convict child abusers and serial killer Ted Bundy. But at least two dozen defendants convicted or charged with murder or rape based on bite marks have been exonerated in the United States since 2000. One of those defendants was Steven Chaney, who spent nearly three decades in prison for the murder of a Dallas man in 1987.
On Thursday, Lynn Robitaille Garcia, the commission’s general counsel, ran through some of the laboratory studies that have highlighted concerns with the accuracy of bite mark comparisons over the past four decades.
Researchers have conducted studies using pig skin, wax and cadavers, making it difficult to simulate real-life cases, and don’t have enough data for reliable statistics. A new study, which was to be undertaken after the state panel’s last meeting in November, has been postponed because forensic odontologists couldn’t agree on certain terminology.
Panel members said the commission on Friday should make recommendations to establish clear criteria or guidelines for identifying what constitutes a human bite mark on skin, for minimizing false negatives and false conclusions, and for distinguishing the difference between an adult bite mark and that of a child.
Without such a foundation, panel members said, the evidence should be kept out of the courtroom.
Chris Fabricant, director of strategic litigation at the Innocence Project, applauded the move. “This commission’s findings are incredibly significant because no other scientific body has ever opined on the admissibility of bite mark analysis, and it is 50 years overdue,” Fabricant said.