The government lawfully used a defendant’s DNA in a criminal prosecution even though its collection during the investigation of an unrelated crime violated the Fourth Amendment, the U.S. Court of Appeals for the First Circuit ruled.

The appeals court on Nov. 22. in U.S. v. Thomas agreed with the defendant, Michael Thomas, that the authorities violated the Fourth Amendment when they obtained his DNA during the U.S. Postal Inspection Service’s prior investigation of suspicious mail sent to his former school. Thomas was never charged in that case, and the investigation closed in 2006.