An exception to the exclusionary rule barring the use at trial of evidence obtained pursuant to an unlawful search and seizure (see the Fourth Amendment). If officers had reasonable, good faith belief that they were acting according to legal authority, such as by relying on a search warrant that is later found to have been legally defective, the illegally seized evidence is admissible under this rule.
Arizona v. Evans is an example of the good faith exception in action: officers relied on a search warrant that turned out to be invalid. In Davis v. U.S., the U.S. Supreme Court ruled that the exclusionary rule does not apply when the police conduct a search in reliance on binding appellate precedent allowing the search. Under Illinois v. Krull, evidence may be admissible if the officers rely on a statute that is later invalidated. In Herring v. U.S., the Court found that the good faith exception to the exclusionary rule applied when police employees erred in maintaining records in a warrant database.