Guns for sale are displayed in Roseburg Gun Shop in Roseburg, Oregon, United States, October 3, 2015. Christopher Harper-Mercer, the gunman slain by police after he killed his English professor and eight others at an Oregon college, was once turned away from a firearms academy by an instructor who recalled finding him "weird" and "a little bit too anxious" for high-level weapons training. REUTERS/Lucy Nicholson