Maryland v. King

Supreme Court of the United States · 2013 · Criminal Procedure

569 U.S. 435 (2013)

Updated July 27, 2026

Criminal ProcedureFourth AmendmentSearches and SeizuresDNA CollectionBooking ProceduresreasonablenessDNA swabbuccal swab

Facts

In 2009 Alonzo King was arrested and charged with first- and second-degree assault for menacing people with a shotgun, and while being booked into custody officers took a DNA sample from inside his cheek under the Maryland DNA Collection Act. The Act authorized DNA collection from persons charged with specified serious offenses, delayed processing until arraignment, and limited use of DNA records to identification-related purposes. King's DNA profile was uploaded to Maryland's database and matched DNA from an unsolved 2003 rape, leading to his indictment and conviction for that rape. The officers complied with the Act's procedures in taking and analyzing the sample.

Issue

Whether the Fourth Amendment permits police, as part of routine booking procedures, to take and analyze a cheek swab of DNA from an arrestee who is in valid custody on probable cause for a serious offense. More specifically, the question was whether this buccal swab and DNA analysis constituted a reasonable search.

Rule

When officers make an arrest supported by probable cause to hold a suspect for a serious offense and bring the suspect to the station to be detained in custody, taking and analyzing a cheek swab of the arrestee's DNA is a legitimate police booking procedure that is reasonable under the Fourth Amendment. The reasonableness inquiry balances the government's legitimate interests in identification and informed custody decisions against the degree of intrusion on the arrestee's diminished expectation of privacy and the minimal physical intrusion of the swab.

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One of 10 multiple-choice questions for this case. Pick an answer to see why.

Police in Cleveland arrest Omar Vega on probable cause for aggravated robbery, a felony categorized by state law as a violent offense. After bringing him to the station for detention, booking officers take a quick cheek swab under a statute limited to serious arrestees and limiting DNA analysis to identification-related CODIS markers.

Omar moves to suppress the DNA profile on Fourth Amendment grounds. How should the court rule?

Explanation. The majority held that when officers arrest a suspect on probable cause for a serious offense and bring the suspect to the station to be detained in custody, taking and analyzing a cheek swab of DNA as part of routine booking is reasonable under the Fourth Amendment. The Court balanced the substantial governmental interests in identification, custody, safety, and informed release decisions against the arrestee’s diminished expectation of privacy and the minimal physical intrusion of the buccal swab.