ince 1963, a series of U.S. Supreme Court decisions has clarified that, in a criminal case, prosecutors must disclose to the defense evidence favorable to the defendant. This includes information that may be used to impeach the credibility of government witnesses, including law enforcement officers. These decisions mean that officers who have documented histories of lying in official matters, falsifying reports, or expressing bias may become even greater liabilities to their agencies because their records may render them unable to testify credibly and consequently unable to work effectively as law enforcement officers.
Supreme Court Cases
In Brady v. Maryland the U.S. Supreme Court held that "the suppression by the prosecution of evidence favorable to an accused upon request violates due process where the evidence is material either to guilt or to punishment, irrespective of the good faith or bad faith of the prosecution."1 In Brady two men were tried for a murder that occurred during a robbery. One of the defendants, Brady, admitted that he had taken part in the robbery but claimed that the other defendant committed the killing. The Court found that the prosecution should have disclosed to Brady's attorney the co-defendant's statements confessing to the killing.
In Giglio v. United States the Supreme Court extended the obligation to share exculpatory information with the defendant to include information concerning the credibility of government witnesses.2 Giglio was convicted of forgery primarily on the testimony of an unindicted co-conspirator. At trial, the co-conspirator testified that he had not received any promises of leniency in exchange for his testimony against Giglio, when in fact the prosecutor who presented the case to the grand jury had promised not to prosecute him in exchange for testifying. The Court was unimpressed with the trial prosecutor's claims that he knew nothing of the deal. "When the reliability of a given witness may be determinative of guilt or innocence," the Court wrote, "nondisclosure of evidence affecting credibility falls within this general rule."
In United States v. Agurs the Supreme Court expanded the rule further by recognizing a duty to disclose exculpatory information even in the absence of a specific request for it.3 The female defendant was convicted of second-degree murder in the stabbing death of a male acquaintance. The defendant had claimed self-defense. After the trial, the defendant learned that the prosecutor had failed to disclose the victim's previous guilty pleas to assault and weapon possession charges. The Court held that the prosecutor's failure to disclose material exculpatory evidence violated due process.
United States v. Bagley further defined "material" evidence as information that, if disclosed to the defense attorney, would have a "reasonable probability of providing a different result in the trial or sentencing."4 This case also clarified that impeachment evidence must be disclosed to the defense. Here, the government failed to disclose contracts with confidential informants who testified against the defendant in his trial on weapons and narcotics charges, which his attorney could have used to impeach their testimony. The Court found that this type of information was material since it would cast doubt on the motives of the witnesses.
Finally, the Court's decision in Kyles v. Whitley imposed upon the prosecutor an affirmative "duty to learn of any favorable evidence known to the others acting on the government's behalf, including the police," and a resulting duty to disclose that evidence to the defense.5 In this case, the defendant was convicted of first-degree murder but was given a new trial after it was discovered that the prosecutor had not divulged exculpatory evidence, even though the prosecutor was unaware of the evidence, which was in police files. The Court stated that even if a prosecutor isn't aware of the exculpatory evidence, "procedures and regulations can be established to carry [the prosecutor's] burden and to insure communication of all relevant information on each case to every lawyer who deals with it."
Federal Law Enforcement's Response to the Disclosure Rules
The bottom line: these Supreme Court decisions create a rule that requires prosecutors to learn of and disclose to the defense information that could be used to discredit law enforcement witnesses in a case. Prosecutors are essentially held responsible for knowing what the police know. The reality is that prosecutors must rely on law enforcement agencies to inform them of a hidden witness credibility problem including, for example, evidence of an officer's prior untruthfulness in official matters.
Responding to this requirement, Attorney General Janet Reno in 1996 established the so-called Giglio policy, which required federal law enforcement agencies to inform federal prosecutors about potential impeachment information. Specifically, federal investigative agencies are required to report prior misconduct involving the officers in a case if that misconduct is "material to the defense" and would damage the credibility of an officer-witness.
This policy places a burden both on the enforcement agency and individual officers to ensure that federal prosecutors are informed about impeachment information. Mere allegations of this type of evidence need not be reported to the prosecutor unless the allegation is determined to be "very credible." However, under this policy, even allegations against the officer that were not sustained, are not credible, or resulted in exoneration may be subject to disclosure if: (1) required by a court; (2) the allegation was made by a federal prosecutor or judge, or received publicity; (3) the agency and the prosecutor agree that disclosure is appropriate under the circumstances; or (4) the agency deems such disclosure is appropriate.
Implications for State and Local Police Departments
Many state and local agencies have similarly begun to disclose to prosecutors any conclusive information regarding untruthfulness, bias, and crimes committed by an officer who is to be a material witness in a criminal prosecution. Once the prosecutor is aware of such information, he or she can decide if the information should be disclosed to the defense attorney.
If the misconduct involves untruthfulness, it is likely to undermine the officer's ability to testify effectively. Agencies have responded to this problem in different ways. Some have adopted strict truthfulness policies and terminate officers who violate them. Other agencies have simply placed officers with impeachment problems in administrative assignments where there is no likelihood of becoming a witness in a criminal case, essentially creating so-called liars squads.
Defense attorneys are using information about untruthful officers to create databases to be used by other defense attorneys. For example, in San Diego, a defense attorney faced with a police witness in a case need only consult a database established by San Diego County Public Defender's Office containing information about local police misconduct and bias.6 If there is information about that officer being untruthful or in some way biased as a witness, the attorney will attempt to use that information to impeach that officer.
As this trend grows, agencies will be required to deal more forcefully with officers who lie. Departments may choose to adopt strict policies regarding truthfulness and rigorously adhere to those policies. Without taking such steps, agencies set themselves up to employ a portion of their commissioned workforce as administrative employees, unable to investigate crimes and testify regarding their investigations. ■