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DNA Profile Is All You Need

A DNA profile is all you need to identify a suspected criminal on an arrest warrant, according to a recent California court ruling.

In August of 2000, with only days left before the statute of limitations ran out on an unsolved sexual assault, district attorneys in Sacramento County filed a warrant for the arrest of a suspect identified only by a DNA profile obtained from the crime scene. One month later, prosecutors found a match in a DNA databank of convicted felons; they arrested Paul Robinson, the first suspect to be arrested on such a warrant.

In a 23 February hearing in Sacramento Superior Court, Robinson's attorney argued that the warrant was unconstitutional because it did not identify the suspect by name. But the judge ruled that the warrant was valid, and that prosecutors were therefore not constrained by the statute of limitations. The defense is appealing.

The decision will have little impact on future cases in California, says Sacramento deputy district attorney Laurie Earl: As of 1 January the state legislature extended the statute of limitations on sexual assault cases in which only DNA evidence is available, putting no limit on the amount of time allowed to find who it belongs to.

But district attorneys in other states will be watching the case closely as a precedent for their own John Doe warrants, says Norm Gahn, a Milwaukee prosecutor who in 1994 filed the first John Doe warrant based solely on DNA. The ruling will allow them to "breathe life" into cases that would otherwise be closed because of statutes of limitations, he says.