Misdemeanor assault charges have been dropped against "24" star Kiefer Sutherland in a head-butting incident at a New York City nightclub, according to Alicia Maxey Greene, spokeswoman for the Manhattan District Attorney’s office. “We decided to drop the charge after a full investigation, including after speaking to a complaining witness, who was uncooperative,” Greene told CNN Tuesday. The charges stem from an incident in which Sutherland allegedly head-butted designer Jack McCollough at a New York City nightclub in May.