MILWAUKEE (Reuters) – An ex-girlfriend of the gunman who killed six worshippers at a Sikh temple in Wisconsin has been arrested and faces a weapon charge, investigators announced on Tuesday. A charge of being a felon in possession of a firearm will be sought through the Milwaukee County District Attorney against Misty M. Cook, 31, according to a brief statement released by the South Milwaukee Police Department. The statement did not say where or when Cook was arrested. …