Category Archives: Impression evidence

Decaying Credibility of Bite Mark Evidence

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No more bite mark evidence?The Associated Press’ Amanda Myers wrote a very interesting article about problems with bite mark impression evidence. “A small, mostly ungoverned group of dentists carry out bite mark analysis,” Myers wrote, “and their findings are often key evidence in prosecutions, even though there is no scientific proof that teeth can be matched definitively to a bite into human skin.”

The Associated Press analyzed court records to learn the number of those who have been exonerated after they were convicted or charged based on bite mark evidence. The results of the study: Since 2000, at least 24 men have been exonerated. Bite mark evidence had thrown one man in prison for more than 23 years.

The validity of bite marks as evidence depends upon two assumptions. First, teeth leave recognizable marks unique to an individual. Second, this uniqueness is transferred and recorded in the bitten substance. Critics argue, however, that neither assumption is supported by scientific studies.

“Bite mark evidence is the poster child of unreliable forensic science,” Chris Fabricant told Myers. Fabricant is the director of strategic litigation at the Innocence Project.

 

Bite Mark Evidence Losing its Bite?

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No more bite mark evidence?

 

The validity of bite marks as evidence depends upon two assumptions: Teeth leave recognizable marks unique to an individual, and this uniqueness is transferred and recorded in the bitten substance. Bite mark evidence has played a key role in cases, such as the trial of Ted Bundy. Yet in recent years, critics argue that bite mark analysis is subjective and has never undergone thorough experimental validation. At least one former bite mark evidence expert agrees.

An August 6 article in The Clarion-Ledger (MS), “Bite Evidence in Doubt,” describes the radical change in views of dentist Michael West. He estimated that he has worked on 16,000 cases and testified at about 81 trials across the United States as a bite mark evidence expert. Many of the trials resulted in convictions.

West is no longer a true believer according to a 2011 deposition obtained by The Clarion-Ledger. “I no longer believe in bite-mark analysis,” West said. “I don’t think it should be used in court. I think you should use DNA. Throw bite marks out.”

That’s advice based on experience. In at least two cases in which the dentist testified, convictions have been reversed. During 2008, for example, DNA evidence identified the murderer of two girls. As a result, two men were released from prison, one who had served 15 years for murder and the other, 18 years.

If Those Lips Could Talk . . .

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A latent lip print visualized

Photo of a latent lip print. Source: Ana Castello et al., “Long-Lasting Lipsticks and Latent Prints,” Forensic Science Communications 4(2) (April 2002).

You’ve heard about fingerprints, footprints, and maybe even ear prints. But what about lip prints?

Around 1990, a U.S. researcher published the results of a 150-lip print study in the FBI Law Enforcement Bulletin, which indicated that a lip print left at the scene of a crime could identify a perpetrator. Despite this endorsement, lip print evidence does not enjoy a wide acceptance in U.S. courts. Nevertheless, the interest in lip prints persists. The field of study is called cheiloscopy.

During March 2012, the Journal of Forensic Sciences published a lip print report online (“Morphologic Patterns of Lip Prints in a Portuguese Population: A Preliminary Analysis”). The study supports the idea that lip prints can distinguish individuals and may be useful in gender determination.