Bitemark analysis is exposed as having serious flaws.

At trial, a more experienced bite-mark analyst from Las Vegas named Ray Rawson confirmed Piakis' findings: The bite marks on Ancona’s neck could only have come from Krone. Rawson included a 39-page report with his testimony. It must have been convincing, because the jury convicted Krone despite no other physical evidence linking him to the crime. He was sentenced to death.
In 1995, Krone was given a new trial after an appeals court threw out his conviction over an unrelated legal technicality. Rawson testified again. And Krone was convicted again. After the second trial, however, the judge refused to sentence Krone to death, writing, "The court is left with a residual or lingering doubt about the clear identity of the killer."The judge’s misgivings proved prescient. Over the strenuous objections of prosecutors, who maintained that Rawson’s testimony was in itself sufficient to affirm Krone’s conviction, Krone's attorney Christopher Plourd was livid that his client could have been convicted not once, but twice, based on obviously erroneous testimony that was presented as scientific. It seemed to confirm what Plourd and other critics of bite-mark analysis have long suspected—that there is little "science" behind the method at all. So in 2001, the lawyer decided to conduct a “proficiency test” on some unknowing and prominent bite-mark expert.
In October 2001, working for Plourd, a private investigator named James Rix sent West the decade-old photographs of the bite marks on Ancona’s breast. Rix told West that the photos were from the three-year-old unsolved murder of a college student in Idaho. Rix then sent West a dental mold of his own teeth, but told him that they came from the chief suspect in the case. He also sent a check for $750, West's retainer fee.
Following the methodology that he has used in more than 100 other cases over the years, West confidently matches a dental mold and a photo of bite marks that have absolutely nothing to do with one another, decorating the fiction with the language of science. Though West is dead wrong, he sounds convincing, and it isn't difficult to imagine how he might prove persuasive to judges and juries.
In February, the National Academy of Sciences published a highly critical report about how forensic evidence is used and abused in the courtroom. The study was especially critical of bite-mark testimony, noting that it has contributed to a number of wrongful convictions over the years. The report concludes that there’s simply “no evidence of an existing scientific basis for identifying an individual to the exclusion of all others” using bite-mark analysis. Yet bite-mark testimony is still common, and there are still plenty of people in prison as a direct result.

Link: http://reason.com/news/show/132574.html