Police and the FBI Violent Crimes Task Force are searching for a man who robbed the Citizens Bank in Union Square on Saturday. At about 11:20 a.m., a man in his 30s or 40s who was wearing jeans and a black and white striped jacket stated that he had a gun, and passed a note to the teller that demanded cash. The suspect fled the building with an undisclosed amount of money. He is between 5 feet, 6 inches and 5 feet, 8 inches tall with a medium build and short brown hair, and was wearing a dark shirt beneath his jacket. Authorities ask that anyone with information about the robbery contact Somerville Police at 617-625-1212, or the FBI at 617-742-5533.