Do police need a warrant to get your DNA?

Amy E. Feldman

An assault took place in Maryland in 2009. Alonzo Jay King was identified by photographs and fingerprints at the scene, and as a result he was arrested and charged with the crime.


While he was being booked for his arrest for assault, under a Maryland statute that allowed the police to take DNA from all people arrested for violent crimes, King’s cheek was swabbed to take a DNA sample even though the police had enough evidence to charge him with the assault.

When the DNA sample was entered in Maryland’s DNA database, it matched the DNA taken from an unsolved rape that happened back in 2003.

King was convicted of second-degree assault for the case for which he was originally arrested; he was also convicted of the 2003 rape based on the DNA evidence and was sentenced to life in prison without the possibility of parole.

King appealed the rape conviction because he says that taking the DNA sample was a search and seizure for which the state should have obtained a warrant. The Fourth Amendment to the U.S. Constitution states:

The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.

Because the state didn’t get the warrant, King argues, it violated his Fourth Amendment right against unreasonable searches and seizures.

The Maryland law that requires the taking of a DNA sample at arrest is, according to King, unconstitutional, and so his rape conviction should be thrown out.

The Maryland Court of Appeals, which heard the case, balanced King’s expectation of privacy from warrantless, suspicionless searches against the state’s right to collect evidence of violent crimes.

But since, according to the court, the authorities investigating the case for which King was arrested—the assault—had enough photographic and fingerprint evidence of the crime, they sided with King, stating: “Although we have recognized (and no one can reasonably deny) that solving cold cases is a legitimate government interest, a warrantless, suspicionless search can not be upheld by a ‘generalized interest’ in solving crimes.” As a result, the court threw out King’s conviction.

The State of Maryland appealed the decision of the Court of Appeals, and on February 26, the U.S. Supreme Court will hear arguments on the question of whether a state may, in fact, take a suspect’s DNA without first getting a warrant to do so.

If you were on the Supreme Court, what would you say? Is taking a DNA sample at the time of arrest different than taking a fingerprint? If so, how? If it is different, should the police be required to get a warrant to take DNA? Should it matter if the DNA sample the police take is a skin sample of cells that can be sloughed off, the swabbing of a cheek, or the taking of hair or blood? How do you balance a suspect’s right not to have his DNA taken against the state’s interest in solving crimes?

The Supreme Court will tell us its opinion by the end of the current term. We’d love to hear your thoughts as well.

Amy E. Feldman is the Legal Education Consultant to the National Constitution Center. She is the General Counsel of The Judge Group, Inc., a leading global professional services based in Philadelphia.

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