A divided Supreme Court ruled Monday that police may take DNA samples when booking those arrested for serious crimes, narrowly upholding a Maryland law and opening the door to more widespread collection of DNA by law enforcement.

The court ruled 5 to 4 that government has a legitimate interest in collecting DNA from arrestees, just as it takes photographs and collects fingerprints. Rejecting the view that the practice constitutes an unlawful search, the majority said it was justified to establish the identity of the person in custody.

“DNA identification represents an important advance in the techniques used by law enforcement to serve legitimate police concerns for as long as there have been arrests,” Justice Anthony M. Kennedy wrote for the majority.

The decision will reinstate Alonzo Jay King Jr.’s conviction in a 2003 rape in Salisbury on Maryland’s Eastern Shore. He was connected to the crime after a DNA sample was taken following an unrelated 2009 arrest for assault.

Law enforcement has found DNA to be a powerful tool in solving cold cases, and the federal government and 28 states allow the practice.

As with other recent court decisions involving the Fourth Amendment’s “right of the people to be secure in their persons, ­houses, papers, and effects, against unreasonable searches and seizures,” the justices split in an unusual fashion.

The dissenters were three of the court’s liberals plus conservative Justice Antonin Scalia, who amplified his displeasure by reading a summary of his dissent from the bench.

“The court has cast aside a bedrock rule of our Fourth Amendment law: that the government may not search its citizens for evidence of crime unless there is a reasonable cause to believe that such evidence will be found,” Scalia said from the bench.

In his dissent, Scalia wrote that the majority’s attempts to justify the use of DNA as an identification tool “taxes the credulity of the credulous.” He added, “Make no mistake about it: As an entirely predictable consequence of today’s decision, your DNA can be taken and entered into a national DNA database if you are ever arrested, rightly or wrongly, and for whatever reason.”

Scalia was joined by Justices Ruth Bader Ginsburg, Sonia Sotomayor and Elena Kagan.

Kennedy wrote that the decision was more limited than that, noting that DNA can be taken only from those suspected of “serious” crimes. He said that police have a legitimate interest in identifying the person taken into custody and that the DNA samples could make sure that a dangerous criminal is not released on bail.

“By comparison to this substantial government interest and the unique effectiveness of DNA identification, the intrusion of a cheek swab to obtain a DNA sample is a minimal one,” Kennedy wrote. Justice Stephen G. Breyer — who most often votes with Ginsburg, Sotomayor and Kagan — joined the opinion, as did Chief Justice John G. Roberts Jr. and Justices Clarence Thomas and Samuel A. Alito Jr.

At the oral argument in the case in February, Alito called it “perhaps the most important criminal procedure case that this court has heard in decades.”

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