A procedure used by police to test the ability of witnesses to identify a person they have seen on a previous occasion—usually the perpetrator of an offence. The procedures are regulated by the PACE Code D. Where the identity of a suspect is not known the witnesses can be taken to an area to see if they can spot the suspect. If the suspect is sufficiently identified and available he should be arrested and a formal identification procedure carried out. The preferred method, which must be the first option, is a video identification. A video identification is when the witness is shown moving images of a known suspect, together with similar images of others who resemble the suspect. Moving images must be used unless: the suspect is known but not available; or the identification officer does not consider that replication of a physical feature can be achieved or that it is not possible to conceal the location of the feature on the image of the suspect. The identification officer may then decide to make use of video identification but using still images. The second method is an identification parade, where the witness sees the suspect in a line of others who resemble the suspect. The next procedure is a group identification where the witness sees the suspect in an informal group of people. The least favoured procedure is confrontation with the suspect. The suspect's consent is not required for this procedure.