In the 2013 case of Maryland v. King, the U.S. Supreme Court ruled that the police are permitted to take a DNA sample of a suspect arrested with probable cause. The court reasoned that extracting a cheek swab of DNA is analogous to taking a fingerprint or a photo of the suspect, and thus a conviction is not needed before doing so. 

            In the dissent of Justice Scalia, he levelled a blistering attack on the majority decision, reasoning that this physical intrusion to obtain the DNA sample amounts to “suspicionless law enforcement searches,” which have nothing to do with the initial reason why the suspect was apprehended, but more to do with building an intrusive data base of the population.