NEW ORLEANS (AP) – U.S. Attorney Jim Letten, whose successful prosecution of a former Louisiana governor and numerous other public officials won him bipartisan praise for more than a decade, resigned Thursday while the Justice Department investigates alleged misconduct by his top deputies.

Letten’s announcement was an abrupt end to his tenure as the nation’s longest-serving U.S. attorney. His crusade against crime resulted in convictions of corrupt judges, killer police officers, bribe-taking officials in New Orleans’ long-troubled school system and scammers who tried to rip off Hurricane Katrina aid programs. He first won fame as an assistant U.S. attorney leading the successful 2000 racketeering prosecution of former Gov. Edwin Edwards.