A three-month Senate investigation has found top Republican staffers systematically downloaded over 4,600 computer files from Democratic offices. The investigation was carried out by the Senate’s top law enforcement officer, Senate Sergeant-at-Arms William Pickle. He made no recommendations about whether to pursue criminal prosecutions but said several federal laws were likely broken. The report identified two staffers, including Manuel Miranda, who became Senate Majority Leader Bill Frist’s top aide on judicial nominations. Both Miranda and the other staffer, Jason Lundell, left their Senate jobs during the investigation.