Recommended Eyewitness Procedures
Scientific Review Paper (Wells et al. 2020)
In Policy and Procedure Recommendations for the Collection and Preservation of Eyewitness Identification Evidence, Wells et al. (2020) give nine recommendations on how to collect and document eyewitness identification evidence:
1. Conduct a Prelineup Interview
Before the identification procedure, officers should interview witnesses as soon as possible after the crime. The interview should be used to obtain a description of the culprit and document (a) the viewing conditions, (b) the eyewitness's attention during the crime, and (c) any prior familiarity with the culprit. At the interview, the eyewitness should be instructed to not discuss the event with other witnesses. The eyewitness should also be advised not to attempt to identify the culprit on their own (e.g., by searching social media). The entire interview should be video-recorded.
2. Use Lineups to Test Evidence-Based Suspicion
Before including someone in an identification procedure for a specific crime, there should be evidence-based reasons to suspect that they are guilty. This evidence should be documented in writing prior to the lineup.
3. Use a Blind Lineup Administrator
Lineups should be conducted using a double-blind procedure: neither the administrator nor the witness should be informed of the suspect's identity in the lineup. If it is not possible to have a blind administrator who is not involved in the case, an alternative method should be used to prevent the administrator from unintentionally influencing the witness (e.g., the witness could view the lineup on their own, without an administrator present).
4. Use Appropriate Lineup Fillers
Lineups should have only one suspect and at least five appropriate fillers, who do not make the suspect stand out based on physical appearance, clothing, or background.
5. Use Appropriate Prelineup Instructions
When inviting an eyewitness to attend a lineup procedure, the police should not provide any new information and should not suggest that the suspect who will be in the lineup has been arrested or that the culprit will be present. The eyewitness should be instructed that the lineup administrator does not know which person is the suspect, the culprit might not be in the lineup, and they have the option of responding "don't know." After making a decision, the eyewitness should be asked to state how confident they are in that decision, and the investigation will continue even if no identification is made.
6. Obtain a Confidence Statement
As soon as a witness makes an identification decision, even if they do not make an identification, they should be asked to provide a statement of confidence.
7. Video Record the Procedure
All aspects of the identification procedure, including prelineup instructions and witness statements of confidence, should be recorded on video.
8. Avoid Repeated Identifications
Avoid conducting a second identification procedure if the eyewitness has already taken part in an identification procedure involving the same suspect, regardless of whether or not the suspect was identified at the first procedure.
Whenever possible, a lineup should be conducted instead of a showup. If a showup is necessary, it should include the procedural safeguards recommended for lineups, such as the removal of suggestive cues, a warning that the detained person may not be the culprit, video recording the procedure, and obtaining a confidence statement.