In April 2009, police easily arrested Alonzo J. King, Jr. in Wicomico County, Md. After King pointed a shotgun at a group of people, one of them told the police who did it, and King readily admitted his guilt. He was originally charged with felony assault and ended up pleading guilty to a misdemeanor.
This seemingly insignificant criminal case is now before the Supreme Court, with arguments later this month. That's because of what the authorities did next. When King was arrested, police took a cotton swab of skin cells from inside his cheek for DNA testing. They did not need his DNA to link him to the shotgun incident. Instead, the police entered King's DNA profile into both the Maryland DNA database and the FBI's national database, CODIS. King's profile, like all those in the database, was then automatically compared every week to evidence from all unsolved crimes. And, in fact, King's DNA matched DNA from an unsolved sexual assault case, for which he was later convicted and sentenced to life in prison.
If Maryland had required King to submit his DNA once he was convicted, then there would be no Supreme Court challenge. So far courts have all upheld DNA collection from felons, reasoning that convicts forfeit some of the rights of ordinary citizens. Maryland v. King is about something new: More than one-half of the 50 states (including Maryland) and the federal government authorize compulsory collection of DNA from people who have been arrested. But the Supreme Court has never held that if police have probable cause to arrest, they can also search a suspect for evidence of past or future crimes. Maryland's justification for this unprecedented expansion of police power? Bigger is better. Add arrestee profiles to the database, and more crimes will be solved.