Madison Police have arrested a 30-year-old man for sending threatening messages to his former girlfriend.  One of those messages included a picture of a gun.  Justin Riley is charged with disorderly conduct, unauthorized use of a computerized device and third-offense operating while intoxicated.  Officers were called to the West Towne Mall Sunday about the situation.  They found Riley driving nearby, stopped his vehicle and found a handgun during a search of his car.