VIDEO: Charged Oklahoma Reserve Deputy Turns Himself In

A volunteer law enforcement officer was booked into jail Tuesday on a manslaughter charge in the death of an Oklahoma man who was fatally shot as he lay on the ground at the officer's feet, reports CBS and the Associated Press.

The Tulsa County (Okla.) Sheriff's Office has said the reserve deputy, a 73-year-old insurance executive who was volunteering on an undercover operation, mistakenly pulled out his handgun instead of his stun gun and shot Eric Harris as the suspect struggled with deputies.

The reserve deputy was charged Monday with second-degree manslaughter involving "culpable negligence" for Harris' April 2 death. If convicted, he could face four years in state prison, reports CBS News correspondent Elaine Quijano.