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Biting Evidence

Here's a special guest post by Pamela King, a Northeastern University journalism student interning with NOVA's web team this semester. She'll take it from here!

He was known as the "snaggle-tooth killer." Ray Krone had been sentenced to death after an impression of his teeth in a Styrofoam cup was used to peg him as the murderer of a Phoenix bartender. The victim had been found with bite marks on her body, but at that time little other physical evidence was available. DNA testing later proved Krone could not have been the murderer, and he was released ten years after his conviction.



Krone's story is just one of many that is leading scientists to study the fallacy of bite mark evidence. Researchers like Daniel Blinka, featured in the video above, are working to standardize the cataloging and matching of bite mark identification so that it might one day be as reliable as DNA evidence.

According to Blinka, characteristics of bite marks have not always been measured accurately and are therefore not yet suitable as courtroom evidence. To address this problem, Blinka, along with a research team, is compiling a database of wax bite mark models from volunteers. The models can then be compared with images of actual bite marks, and the researchers, using specialized software, can measure dental identifiers such as arch width and tooth rotation. Although members of the research team will need to collect many more samples to do so, they hope to eventually use the database to find out how frequently dental characteristics occur in a population.

A recent study conducted at the State University of New York at Buffalo, however, reveals that collecting bite mark evidence may not be as simple as biting into a wax mouthpiece. When a person is bitten, the researchers say, teeth indentations disappear quickly, and only bruised skin remains. This leaves forensic dentists with the difficult task of definitively distinguishing, based on bruising alone, one biter from another whose teeth might be similarly aligned.

The study's authors were among the first to use cadavers in their experimentation, instead of wax or Styrofoam, to better replicate the elasticity of living human skin.

Krone and others have since been exonerated by DNA evidence, but the Innocence Project, a group that works to free wrongfully convicted people, is calling for the scientific validation of any method of evidence analysis employed in cases where lives and liberty hang in the balance.

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Great item.

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