Facial composites and techniques to improve image recognisability

Abstract

There are various types of evidence that can help bring a criminal to justice. Some are valuable at the early stages of an investigation, for instance when a suspect is named from CCTV footage by a member of the public (see Chapter 9). Other evidence is important later and can be used to confirm or refute whether a suspect is likely to have committed a particular offence. A suspect may, for instance, be picked out of an identity parade (Chapter 6), or an expert may be called upon to qualify the match between the suspect’s face and a CCTV image (Chapter 10). In some investigations, however, the available evidence does not result in a suspect being identified. In these situations, the police may ask eyewitnesses to construct a likeness or facial composite of the offender’s face. Facial composites have played a significant role in policing for about four decades. They are primarily used as an investigative tool, to enable a person familiar with the offender (e.g., a police officer or member of the public) to put a name to the face. Until recently, composites had very low correct naming rates (5%), suggesting that few offenders were identified, although this level of performance is arguably better than the alternative of not utilising composites at all.