When the case depends on an officer’s word
Many criminal cases rest on a police officer’s testimony: what the officer saw at a traffic stop, what a suspect said in an interview, how a search was conducted, how evidence was handled. When the officer’s credibility is in question, that question belongs to the defense. The law requires the prosecution to disclose favorable evidence, including evidence that impeaches its own witnesses, and that includes officers.
We defend people in Racine County Circuit Court at 730 Wisconsin Avenue and Kenosha County Circuit Court at 912 56th Street, from our offices in Racine and Kenosha. Our founding partner, Patrick K. Cafferty, has defended Wisconsin felony cases since 1994, and spoke with TMJ4’s Lighthouse team about a vacated murder conviction in which the jury never heard about credibility problems with the lead detective: read that interview.
- The constitutional rule. Suppressing evidence favorable to the accused violates due process when it is material to guilt or punishment, whether the prosecution acted in good or bad faith. Brady v. Maryland, 373 U.S. 83 (1963) (federal constitutional law, binding in Wisconsin).
- Impeachment counts. Evidence that impeaches a prosecution witness is within the rule. Giglio v. United States, 405 U.S. 150 (1972).
- Wisconsin’s three-part test. Favorable, suppressed, material. State v. Wayerski, 2019 WI 11, ¶35.
- The statute. On demand, the district attorney must disclose any exculpatory evidence and the known criminal record of a prosecution witness, § 971.23(1)(f) and (h).
- The ethics rule. A prosecutor must make timely disclosure of all evidence or information known to the prosecutor that tends to negate guilt or mitigate the offense, SCR 20:3.8(f)(1).
- Officers specifically. A district attorney may have a duty to disclose that an officer-witness was accused by another officer of testifying untruthfully in an unrelated case, depending on materiality. 75 Op. Att’y Gen. 62 (1986).
What a “Brady list” is, and what it is not
Prosecutors’ offices keep track of officers about whom they hold information that may have to be disclosed when those officers testify. That record is commonly called a Brady list, after Brady v. Maryland. The obligation behind it does not depend on the list: it comes from the Constitution, from § 971.23, and from SCR 20:3.8(f).
Two consequences follow. An officer’s name on a list does not by itself mean the officer’s testimony is untrue or that every case the officer touched is affected. And an officer’s absence from a list does not mean there is nothing to disclose. The question in each case is the one the law asks: is there information favorable to the defense, was it withheld, and is it material to this case.
What the prosecution has to disclose
Favorable evidence, including impeachment. Under Brady and Giglio, the duty covers evidence that is exculpatory and evidence that impeaches a prosecution witness. The Wisconsin Supreme Court restated the test in State v. Wayerski, 2019 WI 11, ¶35: the evidence must be favorable, because it is exculpatory or impeaching; it must have been suppressed by the State, willfully or inadvertently; and it must be material.
Suppression does not turn on the prosecutor’s intent. Wayerski held that suppression is the nondisclosure or withholding of evidence from the defense, and rejected limits that had required the evidence to be in the State’s exclusive possession, unobtainable by the defense through reasonable diligence, or an intolerable burden for the defense to find. The Supreme Court of the United States has said a prudent prosecutor will resolve doubtful questions in favor of disclosure, and Wayerski quoted that principle.
Materiality. Evidence is material when there is a reasonable probability that disclosure would have produced a different result. Wayerski, ¶36. Wisconsin courts have long recognized three settings with different standards: when the undisclosed evidence shows the prosecution’s case included perjury, when the defense made a specific pretrial request, and when the defense made no request or only a general one. State v. Ruiz, 118 Wis. 2d 177 (1984).
The statute. Under § 971.23(1), upon demand and within a reasonable time before trial, the district attorney must disclose, among other things, the criminal record of a prosecution witness known to the district attorney, § 971.23(1)(f), and any exculpatory evidence, § 971.23(1)(h). The Court of Appeals has held that the State, not the defendant, bears the burden of supplying its witnesses’ criminal records, State v. Randall, 197 Wis. 2d 29 (Ct. App. 1995), and that a witness’s probationary status had to be disclosed even though the jury knew of the conviction, State v. White, 2004 WI App 78.
Officers as witnesses
The Wisconsin Attorney General addressed the officer question directly in OAG 12-86, 75 Op. Att’y Gen. 62 (1986). A district attorney asked whether he had to disclose that one officer had claimed another officer-witness did not tell the truth under oath in an earlier, unrelated case. The Attorney General’s opinion concluded:
- the duty may exist under Brady, because impeachment evidence is subject to disclosure;
- it depends on materiality, which turns on how much the State’s case relies on the officer’s evidence;
- where the State’s case depends exclusively or almost exclusively on the officer’s credibility, a duty to disclose would almost certainly exist; and
- a prosecutor in doubt can ask the trial court to review the material in camera, the procedure described in State v. Denny, 120 Wis. 2d 614 (Ct. App. 1984).
The practical point is the one the opinion makes: the more a case turns on one officer’s account, the more that officer’s credibility history matters, and the stronger the claim to disclosure.
Timing: before a plea, before trial, after conviction
Before a plea. Due process does not require the State to disclose impeachment information before a plea bargain. But a defendant who has made a statutory discovery demand may be entitled to it before pleading, if the plea comes within the time the prosecutor would have been statutorily required to disclose it. State v. Harris, 2004 WI 64. The demand should be made early.
Before trial. Section 971.23(1) requires disclosure within a reasonable time before trial. SCR 20:3.8(f)(1) requires the prosecutor to make timely disclosure of information tending to negate guilt or mitigate the offense, and, in connection with sentencing, to disclose unprivileged mitigating information to the defense and the court.
After conviction. Under SCR 20:3.8(g), a prosecutor who knows of new, credible and material evidence creating a reasonable likelihood that a convicted defendant did not commit the offense must promptly disclose it to an appropriate court or authority and, where the conviction came from the prosecutor’s jurisdiction, make reasonable efforts to disclose it to the defendant. A conviction obtained in violation of Brady can be challenged on that ground. See our appeals and post-conviction page.
Using credibility evidence at trial
Disclosure is the first step; using the information is the second. The Wisconsin evidence code controls how:
- Reputation and opinion. The credibility of any witness may be attacked with reputation or opinion evidence about character for truthfulness, § 906.08(1).
- Specific instances. Specific instances of conduct probative of untruthfulness may be raised on cross-examination, if not remote in time, but may not be proved with extrinsic evidence, § 906.08(2).
- Convictions. A witness’s criminal convictions are governed by § 906.09.
Which of these is available depends on what the disclosed information is, how it was established, and how central the officer is to the State’s case.
How we approach disclosure in a case
- Make the statutory demand at the start. Under § 971.23(1) and Harris, the timing of the demand affects what the defense is entitled to, including before any plea.
- Identify every law enforcement witness. Each officer who stopped, searched, interviewed, arrested, tested or handled evidence is a potential witness whose credibility can matter.
- Request specifically. Ruiz recognizes that a specific request changes the analysis. The defense asks for credibility and disciplinary information about named witnesses, not just “exculpatory evidence.”
- Ask the court when the State hesitates. In camera review lets the judge examine disputed material without disrupting the case.
- Measure materiality honestly. Credibility evidence matters most when the case rests on the officer’s account, and we assess it against everything else the State has.
- Revisit closed cases when new information appears. Information that surfaces after a conviction can support post-conviction relief under the Wayerski test.
Call to talk about your case
Call (262) 632-5000, answered 24 hours a day, or contact Cafferty, Scheidegger & Johnson for a free consultation at 840 Lake Avenue in Racine or 7001 30th Avenue in Kenosha. If you were convicted in a case that depended on an officer whose credibility has since been called into question, call about whether post-conviction review is available. Spanish-speaking clients can read this page in Spanish and speak with attorney Juan S. Ramirez directly.
Related practice areas
- Appeals, parole and probation matters
- OWI and DUI defense
- Drug charge defense
- Resisting or obstructing an officer
- Federal criminal defense
- Patrick Cafferty on TMJ4: an overturned conviction and a detective’s credibility
Sources:
- Wisconsin State Legislature: § 971.23, Discovery and inspection
- Wisconsin State Legislature: § 906.08, Evidence of character and conduct of witness
- Wisconsin State Legislature: § 906.09, Impeachment by evidence of conviction of crime or adjudication of delinquency
- Wisconsin Court System: SCR Chapter 20, Rules of Professional Conduct for Attorneys, including SCR 20:3.8
- Wisconsin Supreme Court: State v. Wayerski, 2019 WI 11
- Wisconsin Attorney General: OAG 12-86, 75 Op. Att’y Gen. 62 (1986)
- United States Reports: Brady v. Maryland, 373 U.S. 83 (1963) (federal constitutional law)
- United States Reports: Giglio v. United States, 405 U.S. 150 (1972) (federal constitutional law)
