Motions to Suppress Eyewitness Identification

Serving as an important safeguard against wrongful convictions, motions to suppress help keep evidence that was gathered improperly or unfairly from consideration at trial. Psychological research has examined the validity of several assumptions underlying the effectiveness of motions to suppress lineup identifications. These studies have examined judges’ and attorneys’ knowledge about eyewitness memory in general and lineup procedures in particular. Research using an experimental paradigm raises some questions on the effectiveness of the motions to suppress lineup identification safeguard. Moreover, judges are applying the criteria outlined by Manson v. Brathwaite (1977), which indicates that the suggestive aspects of the identification procedure should be weighed against the likelihood that the identification is accurate. The two prongs that constitute the Manson test are not independent of each other because suggestive lineup procedures can readily infect the criteria that judges must consider when evaluating the probability that the identification is accurate. Moreover, the identification accuracy criteria that are to be considered have little to do with eyewitness memory or lineup identification accuracy. In summary, there are several reasons to question the effectiveness of motions to suppress lineup identifications as a safeguard against wrongful convictions.

A motion to suppress is a request to the court to exclude evidence on the grounds that it was obtained unfairly or illegally. These motions are typically filed by criminal defense lawyers in an attempt to keep the evidence in question from consideration at a hearing or at trial. A motion to suppress must be accompanied by supporting arguments or facts that speak of the reliability of the evidence or violations of due process under the Fourteenth Amendment. For example, a lawyer may file a motion to suppress evidence that the police obtained during a search and seizure that was conducted without a warrant or without consent. Lawyers may also file a motion to suppress hearsay testimony, confession evidence, or information gleaned during the course of an interrogation. Finally, lawyers may file motions to suppress eyewitness testimony that stems from a police lineup on the grounds that the lineup identification procedure was conducted unfairly.

There is psychological research that bears on issues surrounding motions to suppress lineup identification evidence. A defense lawyer who believes that a witness erred in the lineup identification because the lineup procedure was conducted unfairly or in a biased manner may (and probably should) file a motion to suppress this evidence from relevant hearings and from trial. Such motions are designed to safeguard against wrongful convictions that are the product of mistaken eyewitness identifications produced by suggestive lineup procedures.

Judges’ Sensitivity to Suggestive Lineup Procedures

Psychological research has raised some serious questions about the effectiveness of motions to suppress lineup identifications by challenging the validity of assumptions that form the backbone of this safeguard.

One assumption underlying the effectiveness of motions to suppress the lineup identification as a safeguard is that judges are sensitive to unfair lineups and that their rulings on motions to suppress lineup identifications are a function of their evaluations of lineup suggestiveness and fairness. In an effort to determine what judges know about eyewitness memory and the factors that affect lineup identification accuracy, a few surveys of judges in the United States have shown that judges are aware of some factors that affect eyewitness memory and lineup identification accuracy but not others.

Judges’ knowledge about eyewitness testimony probably plays an important role in their motion rulings. Richard Wise and Martin Safer surveyed 160 judges and found that familiarity with eyewitness memory issues was related to their tendency to permit the use of legal safeguards such as jury instructions on memory issues and expert testimony. The Wise and Safer research did not examine the link between education and motions to suppress, however.

Taking an experimental approach, Stinson and colleagues presented Florida criminal judges with a description of a simulated crime and eyewitness’s description of the perpetrator as well as a photo lineup that varied in terms of the suggestiveness of the lineup instructions, lineup composition (i.e., the extent to which the photos in the lineup matched the eyewitness’s description of the perpetrator), and lineup presentation (sequential or simultaneous). Judges recognized the unfairness of suggestive lineup composition and instructions, and they ruled on the simulated motion accordingly. Interestingly, some judges indicated that they very rarely see these types of motions. Neither the reason for this finding nor the extent to which results generalize to other areas is clear. Until fairly recently, the only record of a lineup procedure was a photograph of the array or the lineup members, so defense lawyers would not be able to evaluate the fairness of the lineup procedure nor obtain much evidence to support a motion to suppress. Additionally, some judges indicated that their general practice was to deny these types of motion; their justification typically revolved around the notion that jurors ought to evaluate and weigh the lineup identification evidence and that judges should not be gatekeepers of this type of evidence.

Defense Lawyers’ Sensitivity to Suggestive Lineup Procedures

Another assumption impinging on the motion to suppress safeguard is that lawyers are sensitive to suggestive lineup procedures and file motions to suppress lineup evidence in these situations. Several survey studies have reported that lawyers recognize some biased lineup procedures such as lineup composition and instructions but not others (e.g., lineup presentation). One experiment tested the effects of biased lineup procedures on defense attorneys’ reactions to the lineup. These data showed that lawyers were sensitive to some unfair lineup procedures. Compared with lawyers who saw a fair lineup procedure, those who saw lineups that were unfair with respect to the composition were more likely to express their intention to file a motion to suppress the lineup identification evidence and predict that a judge would grant such a motion.

Having direct implications for the motion to suppress safeguard, defense lawyers reported that they rarely attend their clients’ lineups. Most lineups are pre-indictment photo arrays during which there is no right to counsel (Kirby v. Illinois, 1972; United States v. Ash, 1973). Thus, it is difficult for defense lawyers to observe and record biased lineup procedures and to substantiate a motion to suppress the lineup identification. In 1999, the U.S. Department of Justice produced guidelines for law enforcement that included a recommendation that lineup identification procedures be documented. In theory, proper recording of lineup procedures ought to contribute toward the effectiveness of the motions to suppress safeguard.

Why the Manson Test Compromises Motions to Suppress

There are also U.S. Supreme Court decisions and case law that speak of the effectiveness of motions to suppress lineup identification evidence. In Simmons v. United States (1968), the Supreme Court ruled that judges should not suppress lineup identification evidence solely because it was gathered in a suggestive manner. Instead, the Court ruled that judges should determine whether the eyewitness identification was likely to be accurate by considering the circumstances surrounding the identification. In subsequent decisions, the Supreme Court further eroded the suggestiveness test by outlining criteria that judges should consider when making their motion decision (Neil v. Biggers, 1972). In the Biggers decision, the Supreme Court proposed that judges consider five factors when determining the reliability of an eyewitness identification: opportunity for the eyewitness to view the perpetrator, the eyewitness’s degree of attention during the crime, the eyewitness’s confidence in the lineup identification, the accuracy of the eyewitness’s description of the perpetrator, and the length of time between the crime and the identification procedure. Psychological research has demonstrated that these five criteria are not particularly predictive of lineup identification accuracy. Finally, in Manson v. Brathwaite (1977), the Supreme Court advised judges to weigh any suggestive elements in the identification procedure against the five criteria outlined in Biggers.

Timothy O’Toole and Giovanna Shay have chronicled how protections against due process violations have eroded since the Manson decision and how this decision has compromised the motion to suppress safeguards. Bringing psychology to bear on this issue, Gary Wells demonstrated the fundamental flaw with the Manson decision. Suggestive lineup procedures can distort several of the self-report criteria spelled out by Biggers, virtually guaranteeing that an identification produced by suggestive lineup procedures would not be suppressed. In other words, the Manson decision makes it unlikely that judges would grant a motion to suppress the identification because they are likely to find at least one of the five redeeming Biggers criteria.

One Connecticut case, State v. Thompson (2004), delineates clearly the flawed analysis in Manson. The Thompson case involves a shooting that seriously wounded the victim, Wesley Gray. Two firefighters at a nearby fire station heard the gun shots, went outside, and saw a man carrying a shotgun. One of the firefighters indicated that he caught a “quick glance” at the man’s face before he returned to the fire station, where he continued to observe the man for a few moments. Subsequently, the firefighter went back outside where he saw the individual climbing a fence. The firefighter retrieved the shotgun, handed it to the police, and provided a description. Shortly thereafter, a police officer drove the firefighter witness to a dead-end alley, the location where other officers had apprehended the suspect. The police officer told the witness that the police had apprehended the person who was “probably the shooter,” shined the headlights from the police car at the defendant, and asked the firefighter to make an identification. The firefighter indicated that he was “absolutely certain” that suspect was the shooter. The defendant, Jerry Thompson, filed a motion to suppress the identification on the grounds that it was highly suggestive and unnecessary, but the court denied the motion because the “totality of the circumstances” indicated that the identification was sufficiently reliable for the jury to consider. The court relied on three of the Biggers criteria for making its decision: the witness was confident, he had a good look at the suspect, and the identification took place shortly after the incident. The defendant was convicted of assault and possession of a firearm; he appealed on several grounds, including that the trial judge erred in denying the motion to suppress, but the appellate court affirmed the trial court’s decision. Neither the trial nor appellate courts recognized that the suggestive identification procedure, perhaps in concert with other factors, can easily distort eyewitnesses’ estimates of their opportunity to view the perpetrator, their confidence in their identification, and their estimate of their “degree of attention” at the time of encoding.

In addition to the obvious calls for eliminating any suggestive aspects of lineup identification procedures and adopting best practices for identification tests, Gary Wells recommends a series of alternatives that would remedy the problems created by Manson. One of these proposed remedies is to shift the burden of proof in situations where the lineup procedure was suggestive so that the prosecutor would have to demonstrate why the identification should be allowed. This is a simple and reasonable solution to this problem. Should this recommendation be implemented in the future, the decision-making process of judges considering a motion to suppress the lineup identification would change.


  1. Kirby v. Illinois, 406 U.S. 682 (1972).
  2. Manson v. Brathwaite, 432 U.S. 98 (1977).
  3. Neil v. Biggers, 409 U.S. 188 (1972).
  4. O’Toole, T. P., & Shay, G. (2006). Manson v. Brathwaite revisited: Towards a new rule of decision for due process challenges to eyewitness identification procedures. Valparaiso University Law Review, 41, 109-148.
  5. Simmons v. United States, 390 U.S. 377, 385 (1968).
  6. State v. Thompson, 81 Conn. App. 264 (2004).
  7. Stinson, V., Devenport, J. L., Cutler, B. L., & Kravitz, D. A. (1997). How effective is the motion-to-suppress safeguard? Judges’ perceptions of the suggestiveness and fairness of biased lineup procedures. Journal of Applied Psychology, 82, 211-220.
  8. United States v. Ash, 413 U.S. 300 (1973).
  9. Wise, R. A., & Safer, M. A. (2004). What US judges know and believe about eyewitness testimony. Applied Cognitive Psychology, 18, 427-443.

See also: