A police lineup is an identification exercise in which a witness to or victim of a crime is required to confirm the presence of a suspect. It is a useful tool for the prosecution since such a positive identification provides direct evidence of the perpetrators crime. These are the three different forms of a police lineup.
The Simultaneous Lineup
In this case, the police officers take the suspect plus other people (known as fillers), arrange them in a random order and ask the witness to identify the perpetrator of the crime in question. There must be at least five fillers in this lineup, and they must all have similar physical attributes. This is to decrease the probability of misidentification. For example, if the suspect needs to wear a hat, then all the fillers must wear hats too. The issue of uniformity also extends to other mannerisms of the lineup. For example, if the suspect is required to shout, then everybody in the lineup shouts.
The sequential lineup is more or less the same as a simultaneous lineup. The main difference is that the witness gets to view the individuals' one after the other, in a random order, rather than all at the same time. For greater accuracy, the witness is allowed to scrutinize each suspect for as long as he or she needs before moving on to the next person. Also, he or she has to see everybody in the lineup even if he or she makes the identification before viewing everybody.
Multiple Identification Lineup
According to psychologists, this is the most accurate form of a police lineup. This format does not involve lining up the actual suspect and fillers; rather it employs the use of photographs. The rationale is that the accuracy of a lineup increases if the physical characteristics of a body – things like face and voice are treated independently.
In a multiple identification lineup, the witness is first given (in a sequential manner) the faces of the suspects. He or she is required to identify the face of the perpetrator. After that, the witness is given sequential recordings, which may be photos or tape recordings, of different physical characteristics. The lineup is most accurate if the witness picks physical characteristics all from the same person.
Whichever lineup you are put through, it's important to have your criminal attorney present. The lawyer ensures that everything possible is done to reduce the probability of misidentification. Your lawyer may also be allowed to have another witness, such as a clerk or a paralegal, to confirm to note any irregularities that may occur during the process.