Identity parade

A police lineup (in American English) or identity parade (in British English) is a process by which a crime victim or witness's putative identification of a suspect is confirmed to a level that can count as evidence at trial.

The suspect, along with several "fillers" or "foils"—people of similar height, build, and complexion who may be prisoners, actors, police officers, or volunteers—stand side-by-side, both facing and in profile. The lineup sometimes takes place in a room for the purpose, one which may feature a one-way mirror to allow a witness to remain anonymous, and may include markings on the wall to aid identifying the person's height.

For evidence from a lineup to be admissible in court, the lineup itself must be conducted fairly. The police may not say or do anything that persuades the witness to identify the suspect that they prefer. This includes loading the lineup with people who look very dissimilar to the suspect.

Photographs of the suspect and fillers can be shown to the identifier in what is called a "photo-lineup", or a "six pack". If the victim or witness successfully identifies the suspect from among the fillers, the identification is considered valid. There is some research into using other methods of photo-lineup that involve the witness sequentially viewing photographs rather than simultaneously.

The sequential method is considered more accurate because it prevents the witness from looking at all the suspects and merely selecting the person that most resembles the guilty person.

A "show-up" is another alternative, in which a suspect is individually shown to a witness.

Many UK police forces use Video Identification Parade Electronic Recording (VIPER), a digital system wherein witnesses view video recordings of suspects and unrelated volunteers.

Sequential lineups is one of the two lineup methods used for eyewitnesses to identify criminals in police station. In a standard sequential lineup, the suspects or their photos are presented one at a time to the witnesses only once. Witnesses make decisions about each individual suspect before the next one is shown and they do not know the total number of suspects.

Although it is hard to pinpoint exactly when sequential lineups were first studied, the knowledge that simultaneous lineups often failed and convicted an innocent person has been common knowledge for many years. The advance of the popularity of sequential lineups can be traced to the Innocence Project and Dr. Gary Wells. Dr. Wells is one of the leading researchers of sequential lineups and has many studies that show that sequential lineups lead to less wrongful convictions. The early studies of sequential lineups found that there was a significant difference in the wrongful conviction of innocent persons. Since these early studies there has been a push to increase the accuracy of eyewitness memory even more.

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Wikipedia