Security has been beefed up in state capitols across the country after at least thirty state governors received threatening letters last week from a leader of a right-wing group called Guardians of the Free Republics. The group called on the governors to step down within three days or be removed. Investigators said they fear the broad call for removing top state officials could inspire individuals to act out violently. The Guardians of the Free Republics has been associated with the sovereign-citizen movement.