Facts
- A robbery and shooting occurred in a Chicago cocktail lounge in 1938, killing an off-duty police officer; Henry Napue was later prosecuted for the officer’s murder.
- A participant, George Hamer, pleaded guilty and received a 199-year sentence; he later became the State’s principal witness against Napue.
- At Napue’s trial, Hamer testified on direct examination that he had received no promise of consideration in exchange for his testimony regarding a reduction of his sentence.
- The prosecutor had in fact promised Hamer favorable consideration and later sought to reduce Hamer’s sentence, stating that a recommendation for reduction had been promised if Hamer testified.
- The prosecutor did not correct Hamer’s false denial at trial.
- The jury heard some information suggesting Hamer hoped for help from a public defender, but it was not told that the prosecutor had made a specific promise.
- Napue was convicted and sentenced to 199 years, with the case against him resting largely on Hamer’s testimony.
Issues
- Whether due process is denied when the prosecution fails to correct testimony it knows to be false, even when the falsehood concerns a witness’s credibility (a promise of leniency).
- What standard governs whether such known false testimony requires relief.
Decision
- The Supreme Court unanimously reversed the Illinois Supreme Court’s judgment affirming denial of post-conviction relief.
- The Court held that the prosecutor’s failure to correct testimony known to be false violated the Fourteenth Amendment’s Due Process Clause.
- The Court rejected the argument that other impeachment evidence cured the constitutional violation.
- The Court independently reviewed the record relevant to the federal constitutional claim rather than deferring to the state court’s factual conclusion.
Legal Principles
- The State may not knowingly use false testimony to obtain a conviction, and the same rule applies when the prosecutor knowingly allows false testimony to stand uncorrected.
- This duty applies even when the false testimony relates only to witness credibility, including undisclosed promises or expectations of leniency.
- Relief is required when the false testimony may have affected the outcome of the trial; the defendant need not show it definitively changed the verdict.
- Evidence of other reasons to doubt a witness’s motives does not necessarily eliminate the prejudice from a prosecutor’s suppression or non-correction of a distinct promise of consideration.
Conclusion
A conviction obtained after the prosecution knowingly leaves uncorrected false testimony about a key witness’s promised benefit violates due process, because the jury is entitled to accurate information bearing on credibility and such falsehoods may affect the verdict.