What we know scientifically continuously changes as new research and advancements in technology become available. One area of interest that was once heavily relied upon in criminal trials has recently been called into question. After a six-month investigation, the Texas Forensic Science Commission (TFSC) recently concluded that criminal trials should cease using bite-mark identifications because the technique’s validity cannot be scientifically established. The commission’s chairman, Dr. Vincent Di Maio, stated that criminal cases should not permit bite-mark testimony because it does not meet forensic science standards. The Texas Legislature created the TFSC in 2005 with the purpose of investigating forensic evidence that is possibly being misused.
During bite-mark testimony, dental experts claim that they can identify marks on victims as those left by teeth and that those supposed bite-marks on a victim can be matched to the dental impressions of a known suspect. The commission, whose findings will be presented in a written report to the Teaxas attorney general, is the first of any official state or federal bodies to recommend the exclusion of this type of testimony. Although it is not legally binding, the recommendation may prove to be extremely significant, and legal experts believe it may have wide-reaching effects on criminal trials nationwide. The recommendation could assist trial judges in deciding whether to allow bite-mark testimony, and may also help defense lawyers prevent wrongful convictions when prosecutors insist on using this unvalidated science in their quest to convict.
In addition to their investigation and conclusion about bite-mark testimony, the commission also began sorting through decades of past trial records. They intend to identify cases that relied heavily upon bite-mark testimony, and therefore should be reopened. According to Dr. Di Maio, although they have not determined in which cases bite-mark testimony was a critical aspect, this type of testimony was involved in 35 convictions that they have identified thus far. He went on to state that the TFSC would alert convicted individuals and defense lawyers who may want to pursue new trials or exoneration at the appropriate time.
Relied upon for decades and used in hundreds of convictions across the country, forensic dentistry specialists used bite-mark testimony to “reliably” match a suspect’s tooth patterns to marks on a victim. As this type of testimony has been increasingly called into question, it has been used less often in recent criminal proceedings and DNA testing has exonerated several people whose convictions were based on bite-mark testimony. In addition, new studies revealed that wound patterns from the same teeth can differ and change shape over time because human skin is very malleable. In fact, in one study that was presented to the TFSC, even a panel of leading forensic dentists could not agree whether human teeth caused the alleged bite marks in the photographs they studied.
The commission hopes that with their new recommendation, researchers will eventually establish thorough principles for identifying human bite marks. They also hope the criteria will include when bite marks can be used in investigations, such as to exclude a person from suspicion or say that they cannot be excluded, rather than to prove one individual left the wounds.
The Innocence Project of Florida is challenging a conviction of a client who was induced into pleading, in part, on problematic bite-mark evidence that the original expert how now recanted. In fact, a battery of forensic odontologists have concluded that the supposed bite-mark purportedly left by our client on the victim’s shoulder was not even a bite-mark at all. Yet, the State continues to oppose relief for our client and is relying on the bite-mark evidence in their attempt to preserve this wrongful conviction.