Computer-aided image analysis of crayfish bitemarks — reinterpreting evidence: A case report

Abstract

The discipline of forensic odontology is at a crossroads with the application of bitemark evidence in the court of law. In the last decade, the increase in the number of cases in which bitemarks were the ‘smoking gun’ to a conviction being appealed and verdicts reverse is alarming and due in a large part to the lack of validated rules and scientific rigor needed to evaluate this evidence objectively. In some cases, post-mortem trauma to human remains has been misinterpreted as human bitemarks. This case report illustrates how bitemarks misinterpreted as human-caused were reevaluated by a computerized imaging analytical method and determined to be consistent with those caused by crayfish scavenging on the remains. Fetal pigs were exposed to crayfish native to the crime scene for a period of 72 h. Crayfish bitemarks on the pigs were compared to marks on the victim and the bite width of the crayfish and found to be statistically the same. These findings led to the exoneration of the convicted individual. Such computer-aided pattern recognition protocols are necessary in traditional forensic identification sciences such as forensic odontology to minimize biased conclusions by extraneous evidence and preconceived assumptions and replace subjective guesswork with sound scientific protocols.