Cupp v. Murphy

Background

Daniel Murphy was tried and convicted in Oregon for the second-degree murder of his wife. After learning of the death he voluntarily came to the police station with retained counsel. Officers saw a dark spot on his finger, asked to take fingernail scrapings, and when he refused they took the samples without a warrant; the scrapings contained victim tissue, blood cells, and fabric and were admitted at trial. State courts upheld the conviction, a federal court of appeals reversed on Fourth Amendment grounds, and the Supreme Court took the case on federal habeas review.

Reasoning

The principal question was whether a very limited, warrantless fingernail scraping during a brief detention (not a formal arrest) violated the Fourth Amendment. The Court noted that three courts had found probable cause to arrest and relied on the Chimel rule about searches incident to arrest and the special danger that fragile evidence may be destroyed. Because the officers faced probable cause, the evidence was highly evanescent, and the intrusion was narrowly tailored, the Court held the brief search to preserve fingernail evidence was constitutionally permissible and reversed the court of appeals.

Real world impact

The ruling allows police, in circumstances where probable cause exists, to take narrowly limited steps to preserve quickly destructible physical evidence during a brief detention even without a formal arrest or a warrant. The decision emphasizes narrow scope and the special destructibility of the evidence, but several Justices stressed that these limits are important to avoid expanding the warrant exception.

Dissents or concurrances

Several Justices concurred while emphasizing narrow limits; two Justices dissented in part, arguing the record left probable cause unclear and urging remand for that determination.