Comparative review of bitemark cases from Pretoria, South Africa.

Bitemark evidence has become more scientifically based and is currently widely accepted in the legal process. Bitemarks can be inflicted by humans or animals on humans, animals and a variety of inanimate objects and can be found on any part of the body, with their quality and appearance being influenced by a variety of factors. The purpose of this study was to record the experiences with bitemark cases presented to forensic odontologists at the University of Pretoria from 1983-1993 and to compare them with trends and findings elsewhere. Sixteen cases are presented, of which 14 were bitemarks inflicted by humans and two by dogs. Thirteen cases occurred in human tissues, three in inanimate objects. Of the bitemarks in human skin, most were present on the arms, followed by the face, thorax and back. Bitemarks over the entire body were seen in the two victims bitten by dogs. The male:female ratio was 4:1 and in 46% of cases single marks were present while the rest were multiple. Eight of the victims had been assaulted. Two cases were associated with sexual behaviour (rape), two were inflicted by dogs, and the circumstances surrounding one case were unknown. A variety of factors complicated the investigations. The major factors responsible for disqualifying bitemarks as evidence included mutilation, removal of tissues, inexperience of officials involved and multiple bitemarks. The results of the study confirm the importance of bitemarks as forensic evidence. Humans are the primary victims with the arm being the anatomical site most often involved. Inexperience on the part of the investigating officers and other officials in the handling of these cases strongly emphasises the need for proper training and education of these personnel.