giglio argued october decided february petitioner filed motion new trial basis newly discovered evidence contending government failed disclose alleged promise leniency made key witness return testimony hearing motion assistant attorney presented case grand jury admitted promised witness prosecuted testified grand jury trial assistant tried case unaware promise held neither assistant lack authority failure inform superiors associates controlling prosecution duty present material evidence jury fulfilled constitutes violation due process requiring new trial pp reversed remanded burger delivered opinion members joined except powell rehnquist took part consideration decision case james la rossa argued cause filed brief petitioner harry sachse argued cause brief solicitor general griswold assistant attorney general wilson jerome feit beatrice rosenberg chief justice burger delivered opinion petitioner convicted passing forged money orders sentenced five years imprisonment appeal pending appeals defense counsel discovered new evidence indicating government failed disclose alleged promise made key witness prosecuted testified government granted certiorari determine whether evidence disclosed require new trial due process criteria napue illinois brady maryland controversy case centers around testimony robert taliento petitioner alleged coconspirator offense witness linking petitioner crime government evidence trial showed june officials manufacturers hanover trust discovered taliento teller bank cashed several forged money orders upon questioning fbi agents confessed supplying petitioner one bank customer signature cards used giglio forge money orders taliento processed money orders regular channels bank taliento related story grand jury petitioner indicted thereafter named coconspirator petitioner indicted trial commenced two years indictment taliento testified identifying petitioner instigator scheme defense counsel vigorously seeking discredit testimony revealing possible agreements arrangements prosecutorial leniency counsel anybody tell time implicated somebody else case prosecuted taliento nobody told prosecuted told might prosecuted believe still prosecuted ever arrested case charged anything connection money orders testified particular time date charged crime know unless still going prosecute issue arose petitioner motion new trial based newly discovered evidence affidavit filed government part opposition new trial confirms petitioner claim promise made taliento one assistant dipaola testified grand jury trial prosecuted dipaola presented government case grand jury try case district golden assistant took case trial filed affidavit stating dipaola assured trial promises immunity made taliento attorney hoey filed affidavit stating personally consulted taliento attorney shortly trial emphasize taliento definitely prosecuted testify testify obliged rely good judgment conscience government whether prosecuted district undertake resolve apparent conflict two assistant attorneys dipaola golden proceeded theory even promise made dipaola authorized disclosure jury affected verdict need concern differing versions events described two assistants affidavits heart matter one assistant attorney first one dealt taliento promised taliento prosecuted cooperated government long ago mooney holohan made clear deliberate deception jurors presentation known false evidence incompatible rudimentary demands justice reaffirmed pyle kansas napue illinois said result obtains state although soliciting false evidence allows go uncorrected appears thereafter brady maryland held suppression material evidence justifies new trial irrespective good faith bad faith prosecution see american bar association project standards criminal justice prosecution function defense function reliability given witness may well determinative guilt innocence nondisclosure evidence affecting credibility falls within general rule napue supra however automatically require new trial whenever combing prosecutors files trial disclosed evidence possibly useful defense likely changed verdict keogh finding materiality evidence required brady supra new trial required false testimony reasonable likelihood affected judgment jury napue supra circumstances shown record neither dipaola authority failure inform superiors associates controlling moreover whether nondisclosure result negligence design responsibility prosecutor prosecutor office entity spokesman government promise made one attorney must attributed purposes government see restatement second agency see also american bar association project standards criminal justice discovery procedure trial extent places burden large prosecution offices procedures regulations established carry burden insure communication relevant information case every lawyer deals government case depended almost entirely taliento testimony without indictment evidence carry case jury taliento credibility witness therefore important issue case evidence understanding agreement future prosecution relevant credibility jury entitled know reasons due process requirements enunciated napue cases cited earlier require new trial judgment conviction therefore reversed case remanded proceedings consistent opinion reversed remanded footnotes dipaola affidavit reads part follows agreed robert edward taliento testify grand jury witness government indicted agreed understood robert edward taliento sign waiver immunity prosecution grand jury eventually testified witness government trial defendant john giglio prosecuted golden affidavit reads part follows dipaola advised taliento granted immunity indicted robert taliento young time alleged occurrence obviously overreached defendant giglio hoey affidavit standing alone contains least implication government reward cooperation witness hence tends confirm rather refute existence understanding leniency