The Supreme Court will decide whether the Fourth Amendment permits police to collect and analyze a person’s DNA at the time of arrest or whether they have to wait until after conviction, reports the Christian Science Monitor. The case raises the thorny issue of when the government is allowed to collect a person's DNA sample and store it in a national database. DNA has become a major crime-fighting tool, providing a significantly more accurate method of identification than the subjective art of fingerprint comparisons.

DNA data have helped police solve crimes and have also helped defense lawyers identify and correct wrongful convictions. Unlike fingerprints, DNA material can reveal far more about an individual, including details that most people consider highly personal and private. The Supreme Court case involves Alonzo King, arrested on an assault charge in Maryland in 2009. The Maryland Court of Appeals reversed his conviction, saying an arrestee has an "expectation of privacy to be free from warrantless searches of his biological material and all of the information contained within that material.”