What Happens in a Police Lineup?

Police lineups are some of the most common tools used by law enforcement to identify criminal suspects. They are not foolproof, and even the best-intentioned officers can unwittingly lead witnesses to pick out an innocent man or woman.

But what actually happens in a police lineup? Here's a basic overview:

Suspect Is Brought In

Almost all police lineups require a suspect who police believe is the perpetrator in a particular investigation. According to Beth Schuster of the NIJ Journal, "[a]t its most basic level, a police lineup involves placing a suspect among people not suspected of committing the crime (fillers) and asking the eyewitness if he or she can identify the perpetrator."

This requires that one or more of the suspects actually be present for the lineup. This can be accomplished by police arresting the suspect and bringing him or her to the police station for the lineup. If officers do not have enough probable cause for an arrest, they may ask a suspect if he or she will voluntarily participate in a lineup.

Believe it or not, just like volunteering to come in for questioning, suspects may actually volunteer for a lineup.

Witness Is Presented With Photos and/or Persons

Once an eyewitness to a crime arrives at the police station, he or she is then presented with pictures of potential suspects or actual live persons:

• In a live (in-person) lineup, the witness observes a line of actual persons -- typically behind a one-way mirror -- which may or may not contain the suspect.
• In a photo lineup, a line or grid of mugshot-style photographs is presented to the witness. Again, this grid may not necessarily contain the suspect.

Schuster notes that it's common for police to practice simultaneous lineups (in which all possible suspects/photos are viewed at once) rather than sequential lineups (photos or persons viewed one at a time.)

A Lineup of Potential Problems

Critics of the use of lineup identification argue that witnesses are often coerced into making identifications even if they aren't certain. Troubling factors may include:

• Lack of similar lineup candidates. If the suspect is 7-foot-4, then placing him with other lineup candidates who are 5-foot-6 introduces major bias.
• Subtle police cues. If officers administering the test know who their suspect is, they may unconsciously cue the witness and ruin the reliability of the test.
• The desire to make an identification. Often, witnesses will feel pressured to make any identification in a lineup even if their memories fail.

Police lineups may be flawed, but eyewitness identification is still highly regarded by criminal juries. If you feel you've been wrongly identified in a lineup, or if you feel a police lineup was improperly conducted, an experienced criminal defense lawyer can help you figure out the best way to proceed.

Related Resources:

• Eyewitness Identification (The Innocence Project)
• What Are Your Rights During a Police Lineup? (FindLaw's Blotter)
• Eyewitness ID Evidence Changed by Landmark NJ Supreme Court Decision (FindLaw's Decided)
• Lineups and Other Identification Situations (FindLaw)