King had been arrested in April 2009 for first-degree assault, which qualified him under Maryland law to have his DNA taken from him (via cheek swab), which upon testing linked him to an unsolved 2003 rape/robbery case. King moved to suppress the evidence, and the U.S. Court of Appeals for the Fourth Circuit agreed, saying that the DNA collection went beyond law enforcement's legitimate needs as to the crime for which King was arrested.
MS. WINFREE: Mr. Chief Justice, and may it please the Court:Lyle Denniston has more. A decision will come sometime later this spring.
Since 2009, when Maryland began to collect DNA samples from arrestees charged with violent crimes and burglary, there had been 225 matches, 75 prosecutions and 42 convictions, including that of Respondent King.
JUSTICE SCALIA: Well, that's really good. I'll bet you if you conducted a lot of unreasonable searches and seizures, you'd get more convictions, too.
JUSTICE SCALIA: That proves absolutely nothing.