What is "police lineup"

Line-up \Line"-up`\, Lineup \Line"up`\ (l[imac]n"[u^]p), n.

1. The members of a team who are scheduled to play a game.

2. Specifically: The formation of football players before the start or a restart of play.

3. Specifically: (baseball) a list of batters in the order in which they will bat. [WordNet sense 1]

   Syn: batting order, card, lineup.

4. Hence: any arrangement of persons (rarely, of things), esp. when having a common purpose or sentiment; as, the line-up at a ticket-office window; the line-up of political factions. [Colloq.]

5. A group of persons including a suspect in a police investigation, arranged so as to be observed by a witness, who is requested to identify the perpetrator, if he/she is present in the group. Such an identification may be used as evidence of guilt of the suspect. Also called a police lineup. [WordNet sense 2]

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.