 An investigation is underway in Milwaukee into the shooting death of a man by police officers in the outer perimeter of the convention. Milwaukee Police Chief Jeffrey Norman says 13 Columbus, Ohio police officers, helping with RNC security, saw a man with two knives charge an unarmed person and ignored commands to drop the weapons. The audio may be disturbing to some. Drop! Drop the knife now! Norman says five officers fired their weapons. Chief Norman says somebody's life was in immediate danger. Jennifer Kuiper, CBS News.