June 17, 2013

Bite-mark evidence derided as unreliable in courts

Critics are questioning its scientific validity and the qualifications of those paid to testify about it.

The Associated Press

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This April 17, 2013 photo shows dental molds that are part of an experiment showing systematic alteration of tooth position to determine when small differences in tooth arrangement can be recognized in bite marks in skin, at the school in Buffalo, N.Y. Bite marks, long accepted as criminal evidence, now face doubts about reliability. (AP Photo/David Duprey)

Richard Souviron
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Forensic odontologist Dr. Richard Souviron points to a photo of Ted Bundy’s teeth during Bundy’s 1979 murder trial in Miami. Souviron, who is considered the founding father of bite-mark forensics, argues there’s a “real need for bite marks in our criminal justice system.”

The Associated Press

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"It's very inflammatory," he said. "What could be more grotesque than biting someone amid a murder or a rape hard enough to leave an injury? It's highly prejudicial, and its probative value is completely unknown."

Fabricant and other defense attorneys are fighting to get bite mark analysis thrown out of courtrooms, most recently focusing their efforts on the New York City case.

It involves the death of 33-year-old Kristine Yitref, whose beaten and strangled body was found wrapped in garbage bags under a bed in a hotel near Times Square in 2007. A forensic dentist concluded a mark on her body matched the teeth of Clarence Brian Dean, a 41-year-old fugitive sex offender from Alabama, who is awaiting trial on a murder charge.

Dean told police he killed Yitref in self-defense, saying she and another man attacked him in a robbery attempt after he agreed to pay her for sex; no other man was found.

Dean's defense attorneys have challenged the prosecution's effort to admit the bite mark evidence, and a judge is expected to issue a ruling as early as mid-June — a pivotal step critics hope could eventually help lead to a ban on such evidence.

A dayslong hearing last year over the scientific validity of bite marks went to the heart of the debate.

"The issue is not that bite mark analysis is invalid, but that bite mark examiners are not properly vetted," Dr. David Senn, of San Antonio, testified at the hearing.

Another case gaining attention is that of William Joseph Richards, convicted in 1997 of killing his wife, Pam, in San Bernardino, Calif., and sentenced to life in prison.

Pam Richards had been strangled and beaten with rocks, her skull crushed by a cinder block, and her body left lying in the dirt in front of their home, naked from the waist down.

Dr. Norman Sperber, a well-respected forensic dentist, testified that a crescent-shaped wound on her body corresponded with an extremely rare abnormality in William Richards' teeth.

But at a 2009 hearing seeking Richards' freedom, Sperber recanted his testimony, saying that it was scientifically inaccurate, that he no longer was sure the wound was a bite mark, and that even if it was, Richards could not have made it.

Shortly after that, a judge tossed out Richards' conviction and declared him innocent. The prosecution appealed and the case went all the way to the California Supreme Court, which ruled in December that Richards had failed to prove his innocence, even though the bite mark evidence had been discredited. In a 4-3 decision, the court said forensic evidence, even if later recanted, can be deemed false only in very narrow circumstances and Richards did not meet that high bar.

Since April 27, Richards' attorneys have been on what they dubbed a two-month "innocence march" from San Diego to the state capital, Sacramento, to deliver a request for clemency to Gov. Jerry Brown and raise awareness about wrongful convictions. They are expected to arrive later this month.

The American Board of Forensic Odontology recently got a request from Richards' attorneys, who are affiliated with the Innocence Project, for a written opinion on the shoddy bite mark evidence used against him. The board declined.

Only about 100 forensic dentists are certified by the odontology board, and just a fraction are actively analyzing and comparing bite marks. Certification requires no proficiency tests. The board requires a dentist to have been the lead investigator and to have testified in one current bite mark case and to analyze six past cases on file — a system criticized by defense attorneys because it requires testimony before certification.

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Ted Bundy



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