Criminals posing as US immigration officers have carried out robberies, kidnappings, and sexual assaults in several states, warns a law enforcement bulletin issued last month by the Federal Bureau of Investigation. The bureau urges agencies to ensure officers clearly identify themselves and to cooperate when civilians ask to verify an officer's identity-including by allowing calls to a local police precinct. "Ensure law enforcement personnel adequality [ sic] identify themselves during operations and cooperate with individuals who request further verification," it says.