The Justice Department's Office of the Inspector General has opened an investigation into the mistaken arrest of Oregon lawyer Brandon Mayfield in connection with March's terrorist attack in Madrid, saying the USA Patriot Act [PDF] may have been improperly used. Mayfield's arrest was based on what turned out to be faulty FBI analysis of a fingerprint.

Details of the investigation are included in the DOJ's semi-annual report to Congress on potential civil rights and civil liberties abuses by Justice Department officials, posted online Tuesday. AP has more. As previously reported on JURIST's Paper Chase, Mayfield has filed suit against the FBI; the specific charges in the suit have not yet been disclosed.