Arizona v. Youngblood

Background

A man convicted of child molestation, sexual assault, and kidnaping appealed after a 10‑year‑old boy identified him. The boy was assaulted, taken to a hospital, and a sexual‑assault kit was used to collect rectal and mouth swabs, saliva, blood, hair, and clothing. The police refrigerated the kit but did not refrigerate the boy’s underwear and T‑shirt. Some forensic tests were later attempted; an ABO blood test on the swab found no blood markers, and a newer P‑30 test on clothing stains was inconclusive. The Arizona Court of Appeals reversed the conviction because the unrefrigerated clothing might have produced exonerating results.

Reasoning

The Court considered whether the Fourteenth Amendment requires the State to preserve evidence that might help a defendant. Relying on prior decisions like Brady, Agurs, and Trombetta, the Court held that when evidence could only “might” have helped, the Constitution does not impose an absolute preservation duty. Instead, a defendant must show the police acted in bad faith in failing to preserve potentially useful evidence. The Court found only negligence here, no suggestion of bad faith, and therefore concluded there was no due process violation and reversed the Arizona Court of Appeals.

Real world impact

The ruling creates a constitutional rule that bad faith by police is required before a federal due‑process remedy for lost or deteriorated evidence. Prosecutors are not constitutionally required to perform any particular tests or to preserve every potentially useful item; the case was reversed and remanded for further proceedings consistent with the opinion.

Dissents or concurrances

Justice Stevens agreed with reversal of this conviction but warned the Court’s broad bad‑faith rule was unnecessary here. Justice Blackmun (with Brennan and Marshall) dissented, arguing the lost semen evidence was constitutionally material and its loss denied a fair trial regardless of bad faith.