State law allowing police to take DNA sample from person arrested for violent crime based on probable cause is constitutional. In 2009, while King was being booked by police on an assault arrest, a cheek swab was taken for typing under the Maryland DNA Collection Act (Act). The DNA linked King to an unsolved 2003 rape, for which he was tried and convicted. He challenged the Act as unconstitutional. The Maryland Court of Appeals reversed, finding the collection of DNA an unreasonable search. Held: Reversed. The Act authorizes Maryland law enforcement authorities to gather DNA samples from persons charged with certain offenses and limits the manner in which the sample may be used–identification. Under the Act, “the arrestee is already in valid police custody for a serious offense supported by probable cause.” This type of search falls within the category of cases the court has evaluated by referring to the proposition that the “touchstone of the Fourth Amendment is reasonableness, not individualized suspicion.” The government has a legitimate interest in correctly identifying an arrested individual, in discovering if he is wanted elsewhere, in assuring the safety of facility staff, and to make sure the arrestee will not flee prosecution. DNA typing is an extension “of methods of identification long used in dealing with persons under arrest.” Balanced against the significant governmental interest at stake, obtaining the DNA sample involves a negligible intrusion of the arrestee, whose status in custody necessarily diminishes his expectation of privacy.