Defending Your Lineup in Court

Armed with headlining DNA exonerations and new research, defense attorneys have a new arsenal for attacking police lineups. Are you ready to do battle in court?

Previously on

Last month in The Hot Debate on Police Lineups we looked at how courts, cops, prosecutors, defense attorneys, politicians, and researchers are all weighing in on what constitutes “best practices” for police lineups. (web link below) The heightened scrutiny has been sparked by:

High profile DNA exonerations.

  1. The fact that mis-identification by eyewitnesses was the leading cause of more than 75% of the wrongful convictions brought to light.
  2. Research into what lineup practices increase the reliability of eyewitness IDs.


Research is continuing because, to date, some disagreement remains. Nevertheless officers can expect, and must be prepared for, cross examination on their lineup procedures. That’s the purpose of this article.

Currently endorsed practices.

The U.S. Department of Justice has two publications for law enforcement on how to gather eyewitness evidence: (web links below)

  • Eyewitness Evidence – A Guide for Law Enforcement
  • Eyewitness Evidence – A Trainer’s Manual for Law Enforcement


These manuals are based on the recommendations of the Technical Working Group for Eyewitness Evidence which included psychology professors, chiefs of police, defense attorneys, prosecutors and others. They represent an effort to unite what psychologists have learned about memory with the practical needs of law enforcement to use eyewitness evidence as an investigative tool.

The American Bar Association, police groups and state commissions have issued their own best practices. Examples include: (some web links below)

  • In 2004, the American Bar Association issued its Best Practices for Promoting Accuracy of Eyewitness Identification Procedures.
  • In 2009, the Commission on Accreditation for Law Enforcement Agencies (CALEA) adopted two new standards (42.2.11 and 42.2.12) addressing eyewitness identification.
  • The IACP revised its model policy on eyewitness identification in September 2010 to take the latest research into account.
  • Wisconsin Model Policy and Procedure for Eyewitness Identification.
  • New Jersey Attorney General Guidelines for Preparing and Conducting Photo and Live Lineup Identification Procedures.


Police agencies that do not have written policies are coming under scrutiny and criticism. State legislatures have stepped in to require law enforcement to develop written policies and procedures. (web links below to Texas)

Best practices MAY include, but are not limited to:

  • Avoiding “showups” (aka field identifications – showing suspect to witness in close proximity to and time of the crime) whenever possible in favor of photo or subject lineups. If a showup is necessary, following strict guidelines such as those in the IACP model policy.
  • Replacing simultaneous lineups with sequential lineups. In simultaneous lineups the witness views all the people or photos at the same time. In sequential lineups, people or photos are presented one at a time. Some research claims that in simultaneous lineups witnesses compare photos or subjects to each other rather than to their memory of the offender. When the real perpetrator isn’t present, the witness will often choose the subject who most closely resembles the offender. In comparison, sequential lineups have the witness compare each subject to their memory of the offender.
  • Using blind administrators who do not know the identity of the suspect to avoid any inadvertent suggestibility.
  • Informing the witness the administrator does not know the suspect and the suspect may not be in the lineup.
  • Adhering to specific guidelines regarding the composition of the lineup – number, similarity in features, placement of suspect, type of photo, etc.
  • Separating eyewitnesses and placing the suspect photo or subject in a different position in each lineup.
  • Obtaining a statement of degree of confidence by the witness at the time of the lineup identification. Some research indicates witness confidence may be increased by the mere fact of learning they “correctly” identified the suspect. Such change in confidence can inflate their perceived recollection of the actual event, i.e., they will now recall seeing the suspect better; getting a better, longer look.
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