It is recommended that the same investigator who collects the bitemark evidence should NOT also collect evidence from the suspect to avoid the inadvertent introduction of bias. The evidence to be collected from the suspect includes dental impressions, buccal DNA swabs, photographs of the dentition and bite exemplars showing the upper and lower teeth.
- DNA Collection:
DNA swabs of the suspect should be collected by trained technicians who possess knowledge and experience in DNA collection, handling and storage proper protocols for the collection and storage of DNA should always be employed.
Photography is the best and most common method of the collection and preservation of the suspect dentition. The use of a quality digital camera system for the photographic documentation of this evidence is recommended. The quality and capabilities of the digital photographic equipment is constantly improving and changing; thus, no suggestions for a specific type of digital imaging system will be recommended. The photographic techniques involved in the evidence collection should include the following:
- full face image
- macro image of the anterior teeth closed together
- macro image of the anterior teeth slightly open
- right and left lateral canine images
- upper and lower occlusal images
- Exemplar of Biting Edges of the Anterior Teeth:
The exemplar should ideally capture the biting edges of the upper and lower anterior teeth without biting through the exemplar. Commonly used exemplars include Aluwax® and Coprwax® (Figure 3).