Steven Chaney was freed from prison in October after 28 years after “bite-mark” testimony against him was debunked. He is is one of more than a dozen people in the U.S. who have been released or exonerated in cases involving bite-mark testimony, the New York Times reports. Chaney had been sentenced to life in prison after a dental expert testified that it was virtually certain his teeth had produced marks on the arm of a drug dealer who was stabbed to death.
Since Chaney's trial in 1987, studies have shown that dental experts cannot reliably claim that a bite wound was caused by a particular individual. They cannot even agree on whether wounds were caused by bites at all. The Texas Forensic Science Commission is seeking to develop guidelines on whether bite-mark comparisons should have any role in the courtroom. The Times says forensic science is in turmoil as prosecutors, defense lawyers and judges confront evidence that many long-used methods, like handwriting analysis and microscopic hair comparisons, were based more on tradition than science and do not hold up under scrutiny. Even fingerprint and certain kinds of DNA matches are not quite so certain as many once believed. No technique is under stronger attack than the analysis of supposed bite marks, a method made famous in the televised trial of Ted Bundy in 1979.