New efforts are underway to crack a cold case murder in Dunbar that marked its 13th anniversary Saturday. 62-year old Dianna Withrow was beaten to death on Jan. 4, 2007, at her home along 18th Street in Dunbar. Her daughter, Maria Bayer, is asking anyone with information to come forward. Dunbar police and county detectives are both involved in the investigation. Kanawha County Sheriff’s Office spokesman Sgt. Brian Humphreys said new detectives have been assigned to the case and they’re reviewing old information and asking for new clues. Withrow’s brother has offered a $5,000 reward for information that would solve the case.