15: Identifying the Individual

It is critical in any investigation that any individual who has committed a crime can be positively identified. Identification can be achieved through the DNA analysis of body fluids as described in Chapter 16 or, as explored here in this chapter, using various features of the body and the impressions left by them, as they can also provide a means of identification and individualisation, both for crime investigation and for biometric purposes. The principal feature used in this way is a fingerprint, and the majority of the chapter focuses on the way in which fingermarks are deposited, visualised, and photographed in order to provide an image for comparison with fingerprints held on a database. A description is also given of the approach used by examiners when conducting a fingermark comparison in criminal identification, in particular focusing on the recent attention that has been given to the potential for contextual and cognitive biases to influence decision making. Finally, an overview is given of the concept of a biometric system and the way in which biometrics such as fingerprints are enrolled into databases. The way in which biometrics could impact on criminal investigations in future is also discussed.