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Researchers Create Bite-Mark Database

May 15, 2008

Although the use of bite marks as evidence in criminal trials has been looked down upon by some forensic experts, researchers at Marquette University claim to have developed a new computer program capable of measuring bite marks.

Researchers said they hope it will lead to a substantial database of bite characteristics that can be used as notable evidence in criminal prosecutions.

“The naysayers are saying, ‘You can throw all this out. It’s junk science. It’s voodoo. This is a bunch of boobs that are causing a lot of problems and heartaches for people,’” said team leader Dr. L. Thomas Johnson, a forensic dentist who helped identify victims of the cannibalistic Milwaukee serial killer Jeffrey Dahmer.

“It’s a valid science if it’s done properly.”

However, some experts disagree.

Dr. Mike Bowers, a deputy medical examiner in Ventura County, Calif., and a member of the American Board of Forensic Odontology, called the new work “scientifically illiterate.”

Forensic dentistry has been used to identify criminals for about 40 years, but critics say that human skin distorts the imprints until they are almost unrecognizable, which leads to differing opinions during courtroom trials.

“If the discipline lends itself to opposing experts, it’s not science,” said Peter Neufeld, co-director of the Innocence Project.

At least seven people in five states have been convicted due largely in part to the use of bite characteristics as evidence, according to the Innocence Project, which aims to free wrongfully convicted inmates.

In 1992, Ray Krone was found guilty of murder based largely on expert analysis that his teeth matched the bite-marks on the victim. DNA testing in 2002 proved that Krone wasn’t the killer. Krone was freed and won a spot on the ABC reality show “Extreme Makeover” to remake his teeth.

In another case in Mississippi, forensic oncologist Dr. Michael West testified in two child rape-murders, which led to the conviction of Kennedy Brewer, who was sentenced to death in one case, and Levon Brooks got life in prison in the other.

After DNA tests were conducted, scientists discovered that a third person was involved with one of the rapes, and investigators say he confessed to both murders.

Brewer and Brooks were exonerated earlier this year.

However, Johnson and his team are determined that that bite analysis can be done scientifically. After receiving almost $110,000 in grants from the Midwest Forensic Resources Center at Iowa State University, researchers designed a computer program aimed at building a database of characteristics such as tooth widths, missing teeth and spaces between teeth.

Johnson’s team anticipates collecting more impressions from dental schools to widen the database.

With enough samples, the software could help forensic dentists answer questions in court about how rarely a dental characteristic appears in the American population. That would help exclude or include defendants as perpetrators, Johnson said.

“This is the first step toward actually providing science for this type of pattern analysis,” Johnson said, acknowledging that bite-mark characteristics alone probably won’t provide enough evidence to lead to a conviction.

Dr. Robert Barsley, a Louisiana State University dental professor and vice president of the American Academy of Forensic Science, said he, too, would send Johnson hundreds of bite impressions.

“His work could certainly be a benefit,” Barsley said. “I don’t think it will solve the problem, but it would be a step in the right direction.”

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