Also known as:potentially exculpatory evidences · Brady material · exculpatory evidence
Written by attorneys · grounded in primary & secondary sources — see below
Evidence whose preservation or disclosure could tend to negate a defendant's guilt or mitigate punishment.
Sources & Authorities
How it applies
Common Examples
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Habeas Substitute Lacks Exculpatory Review
U.S. naval forces detained Philip Powell on a floating platform after intercepting his vessel near an armed conflict zone. A federal statute channeled all challenges to a maritime security board that could not consider newly discovered shipping records or crew testimony and lacked power to order release. Powell filed a habeas petition arguing the statute denied meaningful review because the board could not evaluate potentially exculpatory evidence discovered after the initial designation.
Prosecutor Withholds Favorable Lab Report
The prosecutor received a lab analysis showing the pathogen in victims' samples was absent from all kitchen swabs at Penelope Price's hotel. Despite possessing this report, the prosecutor filed charges against Price based solely on guest affidavits. Price's counsel later discovered the withheld analysis and moved to dismiss, arguing the failure to disclose material potentially exculpatory evidence violated due process.
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Cases
Casebooks
Hearsay Rule Bars Critical Defense Testimony
Paula Pierce sought to introduce a reliable out-of-court statement from a witness who had since died, stating that another person admitted committing the charged offense. The trial court excluded the statement under the hearsay rule. Pierce argued on appeal that the strict application of hearsay rules violated due process by excluding trustworthy, critical potentially exculpatory evidence essential to a fair trial.
Counsel Fails to Investigate Exculpatory Records
Pierce Patterson pleaded guilty after his lawyer failed to obtain maintenance logs showing the vehicle brakes had been inspected days before the accident. Patterson later learned the logs would have supported a defense that the other driver's sudden stop caused the collision. He claimed the failure to discover this potentially exculpatory evidence prejudiced his plea decision.
Hill v. Lockhart474 U.S. 52 (1985)
Presumption Shifted Without Exculpatory Opportunity
Pedro Pacheco was charged with possessing a controlled substance found in a car he occupied with three others. A state statute created a presumption that all occupants possessed the drugs. Pacheco sought to introduce evidence that one passenger had admitted sole ownership, but the trial court limited his ability to rebut the presumption with this potentially exculpatory testimony.
County Court of Ulster County, N. Y. v. Allen442 U.S. 140 (S.Ct.1979)
Voluntary Intoxication Evidence Excluded
Pavel Petrov was charged with deliberate homicide after a bar fight. State law barred evidence of his voluntary intoxication to negate the mental state element. Petrov argued the exclusion prevented him from presenting potentially exculpatory evidence that he lacked the required mens rea due to extreme intoxication, violating due process.
Montana v. Egelhoff518 U.S. 37, 116 S.Ct. 2013, 135 L.Ed.2d 361 (1996)
Common questions
Frequently Asked
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What distinguishes potentially exculpatory evidence from material exculpatory evidence under Brady?+
Potentially exculpatory evidence refers to items whose contents might exonerate the defendant if known or preserved. Brady requires disclosure only when the evidence is both favorable and material to guilt or punishment. Failure to disclose material exculpatory evidence violates due process whether the suppression is intentional or inadvertent.
Supporting sources
Does the government have a duty to preserve all potentially exculpatory evidence?+
No. The Due Process Clause does not impose an absolute duty to retain every item that might conceivably be of evidentiary significance. When evidence is lost, courts must assess whether the loss was in bad faith and whether the evidence was of such a nature that its exculpatory value was apparent before destruction.
Supporting sources
How does potentially exculpatory evidence factor into habeas review for enemy combatants?+
A meaningful substitute for habeas corpus must permit detainees to introduce exculpatory evidence discovered after initial proceedings and to seek release if the evidence undermines the detention justification. A review process that bars new exculpatory evidence or lacks authority to order release fails constitutional standards.
Supporting sources
518 U.S. 37, 116 S. Ct. 2013, 135 L. Ed. 2d 361 (1996)Criminal Law
…to introduce crucial, relevant evidence: " In the absence of any valid state justification, exclusion of this kind of exculpatory evidence deprives a defendant of the basic right to have the prosecutor's case encounter and survive the crucible of meaningful adversarial testing." 476 U. S., at 690-691 (emphasis added) (internal…