A top immigration official accused of misleading Congress on whether a Clinton administration program was used to allow thousands of foreign nationals with criminal records to become U.S. citizens now heads a fraud and national security program at the Department of Homeland Security. Louis D. "Don" Crocetti, whose credibility before a House subcommittee was challenged by the Justice Department's Office of Inspector General, now heads the Office of Fraud Detection and National Security, which, among other things, is responsible for criminal background checks on foreign nationals seeking naturalization. The appointment was quietly announced in May by Eduardo Aguirre, director of...