By Lawrence Hurley

WASHINGTON (Reuters) - In a case that spotlights the growing use of genetic data by law enforcement agencies, the Supreme Court will consider on Tuesday when a DNA sample may be taken from a suspect.

Police and prosecutors in Maryland suffered a major setback when the state's court of appeals ruled in April 2012 that Alonzo King's Fourth Amendment right to be free from unreasonable search and seizure was violated when he was required to provide his DNA upon being arrested.

Under Maryland law, samples can be taken from anyone arrested for a serious offense without police needing to get a warrant first. Police can then submit those samples to a national database to see if the suspect is linked with any other crimes.

The case being argued Tuesday focuses purely on samples taken after a suspect is arrested and charged with a crime, but not convicted of it. Samples taken from convicted felons are routinely submitted to the national database. That practice is not an issue in the case.

The sample King gave after a 2009 arrest in Wicomico County on two assault charges linked him to a 2003 rape. He was sentenced to life in prison after being convicted of the rape and was convicted of one count of misdemeanor assault on the 2009 charges.

His lawyers argue that the sample taken in the assault arrest should not have been used to link him to the rape.

The nine members of the U.S. Supreme Court will review the Maryland court ruling during a one-hour oral argument.

King has received full-throated support from civil liberties groups, which are concerned that the government has too few constraints in collecting DNA. At a minimum, police should be required to get a warrant, based on what lawyers call "individualized suspicion," that links a suspect to a particular crime, King's backers say. There was nothing linking King to the rape until after his DNA was taken and submitted to the database.

Maryland Attorney General Douglas Gansler, a Democrat, said in an interview that the state court decision "didn't make a whole lot of sense to us." He described the law enforcement community in Maryland as being "apoplectic" when the ruling came out.

"The importance of DNA to law enforcement cannot and should not be lost on the justices," Gansler said.

FIFTY STATES

Gansler and his law enforcement allies make a sweeping argument about the government's right to take DNA samples. They insist that the act itself - which takes the form of a swab of the inside of the cheek - is reasonable, and therefore permissible, under the Fourth Amendment, even when there is no warrant.

Factors to take into account include the minimal intrusion of the search and the interest of the state in identifying and supervising suspects before trial, the state's lawyers say.

State law enforcement groups, including the Maryland Chiefs of Police Association, filed their own brief in the case, noting that the collection of DNA from people who have been arrested "is a critical and effective modern tool."

A ruling in favor of King would cast into doubt 27 similar state laws and a complementary federal law. Every other state in the country, plus the District of Columbia and Puerto Rico, signed on to a brief in support of Maryland.

There are multiple benefits, California Attorney General Kamala Harris wrote in the states' brief. Continued...