Police say 39-year-old Charles Vacca was instructing a 9-year-old girl on how to shoot an automatic weapon when he was accidentally shot in the head.
Video taken just moments before the deadly accident may shine a light on what went wrong. After firing a single shot, the instructor set the weapon to fully automatic. According to the Mohave County Sheriff's Office the gun rotated backwards while still firing and shot Vacca.
Read more from NBC News.
Copyright 2016 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.