Maryland v. King

Background

In 2003 a woman was raped and police kept a DNA sample from the crime. In 2009 a man hiding a gun was arrested on a separate assault charge. During routine booking his cheek was swabbed for DNA under Maryland's DNA Collection Act. Months later the swab was added to the state database and matched the 2003 sample, leading to his indictment, trial, and conviction. Maryland's highest court ruled the booking swab unconstitutional and set aside the rape conviction; the Supreme Court reversed.

Reasoning

The Court framed the key question simply: whether taking and testing a cheek swab from someone arrested for a serious offense is an unreasonable search. Justice Kennedy's opinion accepted that a buccal swab is a search but concluded it is a minimal intrusion. The Court weighed government interests—confirming identity, protecting staff and the public, preventing flight, and solving unsolved violent crimes—against the privacy invasion, noting the swab uses only noncoding DNA markers and the Maryland law restricts testing and storage to identification purposes. Comparing DNA collection to fingerprinting and photographing at booking, the Court held the search reasonable under the Fourth Amendment and reversed the state court.

Real world impact

The ruling allows police in Maryland and other jurisdictions with similar laws to collect and test DNA from people arrested for serious crimes as part of booking. The opinion notes that about twenty-eight States and the Federal Government have similar arrestee DNA laws and that CODIS connects local and national DNA databases. The decision makes it more likely that arrests will lead to matches in unsolved violent cases, affecting investigations, pretrial custody decisions, and how quickly cases are solved.

Dissents or concurrances

Justice Scalia dissented, joined by three Justices, arguing the practice is a suspicionless search aimed at solving crimes rather than identifying arrestees, pointing out statutory limits on testing before arraignment and delays in actual processing that undermine the majority's identification rationale.