Judicial gatekeeping of police-generated witness testimony.

• Author: Thompson, Sandra Guerra
• Position: Introduction through II. The Unreliability Conundrum, p. 329-364

1. INTRODUCTION

   Wrongful convictions prove that sometimes verdicts of guilty "beyond a reasonable doubt" are dead wrong. Erroneous guilty verdicts often rest on three types of central--and often unreliable--lay witness testimony: eyewitness identification testimony, police officer testimony regarding a defendant's confession, and a police informant's (2) testimony regarding a defendant's incriminating statements. (3) Unlike other lay witness testimony, police-generated testimony (4) in criminal cases is often rendered unreliable by suggestive or coercive police conduct or by police incentives to lie. (5) This is a critical factor that distinguishes other forms of testimonial evidence from this type of evidence. The role of the police in procuring these statements is a critical factor in assessing the reliability of confessions, informant testimony, and eyewitness identifications.

   In an important sense, the evidence can be viewed as the product of the interaction between the individual, on the one hand, and the police investigator on the other. These types of evidence are not simply "found" in the way that a murder weapon may be found at a crime scene. Instead, a piece of these types of police-generated witness testimony may be likened to trace evidence, in that it must be carefully collected and processed in order to make accurate determinations. It is the interaction of the investigator with the individual giving statements that ultimately produces relevant evidence, and improper handling can contaminate or destroy the evidence. (6) Extensive studies have shown the effects that certain law enforcement practices can have in rendering police-generated witness testimony of these three types unreliable. (7) Reliability concerns have even led a few jurisdictions to prohibit death sentences based solely on these types of evidence. (8) Thus, a major contribution of this Article is to catalogue the ways in which all three of these types of prosecution evidence can be rendered substantially more unreliable by strong-armed police tactics, especially when they are employed against individuals who are particularly vulnerable, such as minors and the intellectually disabled or mentally ill.

   A number of proposals have called on trial courts to play a gatekeeping role for police-generated witness testimony that mirrors the role they ostensibly play in screening scientific evidence for reliability as outlined by the Supreme Court in Daubert. (9) Just as with forensic evidence, there are best practices for gathering and preserving these types of evidence. Laboratory protocols guide the scientist, and standardized protocols can guide law enforcement in gathering and preserving eyewitness identification evidence, confessions during custodial interrogations, and the use of police informants. (10) If investigators "contaminate" the evidence by using suggestive or coercive practices, it is within the province of the trial judge to exclude the resulting evidence as too unreliable or to devise a less drastic intermediate remedy.

   Unfortunately, the analogy to scientific evidence--another common cause of wrongful convictions--suffers from the fact that trial courts generally have either been unwilling or unable to perform competent reliability screening in criminal cases. (11) To be fair, reliability in the context of scientific evidence presents a more challenging task for courts. (12) Evaluating the scientific validity of a proposed expert's testimony involves a complex assessment of the established scientific theory, the accepted protocols for obtaining such evidence, and the applicability of the science to the facts of the case at bar.13 Scientific expertise also comes in a myriad of varieties, and each type of evidence requires the court to assess reliability on numerous, complex levels. (14) Not surprisingly, grave concerns about the unscientific nature of much forensic evidence admitted by courts persist. (15)

   It hardly makes sense to propose expanding on a failed model of reliability screening. However, courts are better suited to conduct reliability screening for police-generated lay witness testimony. The term "reliability" as used here means simply accuracy, and it operates in reference to the trial outcome. Determining reliability in relation to confessions, eyewitness identifications, and informant testimony involves a probabilistic assessment of the extent to which a variety of factors known to diminish the accuracy of these types of evidence are present in a given case. Judges can simply compare the police procedures followed in the case to state-of-the-art best practices that have been developed by law enforcement groups and reformers. A reliability assessment would also necessarily take into account any vulnerability factors, and other intrinsic factors pertaining to the individuals interviewed, that are known to reduce the likely accuracy of the statement given. (16)

   Traditionally, trial courts hold pretrial hearings for confessions and eyewitness identification evidence, but only to determine whether it was obtained in accordance with the defendant's constitutional rights. These hearings have not been effective in ensuring the reliability of the evidence. (17) A new landmark decision by the New Jersey Supreme Court sets a new course for its state due process analysis of eyewitness identifications by requiring pretrial reliability hearings of the type advocated here. (18) This opinion can serve as a template for other states in vastly improving the screening of identification evidence and the use of jury instructions. It also sets an important precedent in that it departs entirely from a failed federal constitutional test for police-generated lay witness testimony. It lays the responsibility for reliability assessment squarely at the feet of the judiciary as a protection for the innocent against wrongful conviction. In this broader sense, it lays the groundwork for a similar departure from the federal voluntariness test for confessions and the development of judicial reliability screening for informant testimony.

   However, state trial courts need not wait for the supreme courts in their states to follow the New Jersey high court's lead. The state counterparts to the Federal Rules of Evidence also govern reliability. Traditionally, we would look to the hearsay rules to guard against the use of unreliable hearsay statements. However, the hearsay rules were drafted long before the advent of DNA exonerations brought to light the potential unreliability of police-generated evidence. For most hearsay, the rules require proof of certain indicia of reliability. In contrast, the rules freely admit confessions, eyewitness identifications, and informant testimony without any reliability screening. (19)

   Fortunately, the drafters of the Federal Rules of Evidence showed the foresight to know that specific rules might not always provide sufficient protection against evidence that might lead to an inaccurate verdict by misleading or confusing the jury or unfairly prejudicing a party. (20) Thus, Rules 701 and 403 vest trial courts with broad discretion to determine whether evidence offered by a lay witness is inadmissible on the grounds that it presents a high risk of unreliability that may lead to an inaccurate verdict. This approach is consistent with the traditional role of the trial judge as evidentiary gatekeeper under Rule 104(a) as well. As our understanding of the dangers of a particular type of evidence may change, the rules should be adapted to meet the challenges presented by this new information. The "purpose and construction" provision of the rules calls on courts to interpret the rules over time so as to "promote the development of evidence law, to the end of ascertaining the truth and securing a just determination." (21)

   Courts have not traditionally held pretrial reliability hearings. Instead, the practice is to leave it to the jury to "find the facts" based on "witness credibility," among other things. (22) Witness "credibility" refers to the witness's truthfulness. However, eyewitnesses who misidentify an innocent suspect and police officers who testify to a suspect's false confession usually give truthful testimony. These witnesses actually believe that the defendant is guilty. The witnesses are "credible" in that they are not lying, but their testimony is nonetheless incorrect. Juries generally do not appreciate the ways in which certain police tactics can cause an eyewitness to make an honest mistake or to feel pressured to identify a certain person, honestly convincing himself of the defendant's guilty. (23) Jurors also generally do not understand how other tactics can cause an innocent person to confess falsely. (24) Similarly, jurors have been shown to be generally ineffective at evaluating the reliability of police informants because they do not appreciate the government incentives or coercion likely to cause informants to lie, nor do they appreciate the vulnerability of some informants in the face of police pressure.

   Pretrial reliability hearings would transform the judicial role from one of passively admitting what may be patently unreliable evidence to one that involves actively scrutinizing the process by which the police have generated the witness testimony. Jurors already understand that trial courts rule on the admissibility of evidence, so freely admitting police-generated witness testimony may be assumed to indicate a judicial imprimatur, giving jurors a false belief that the judge considers the evidence reliable. Moreover, the reliability of police-generated witness testimony cannot properly be screened during a trial by a jury. The issues are better suited to a pretrial hearing regarding the conditions under which police interviewed the individual, as well as other reliability factors. As an institutional matter, judges through training and experience can develop the required...