Authorities investigating fatal shooting in Atoka County

ATOKA COUNTY, Okla. (KXII) -- Authorities are investigating after a 20-year-old said a rifle fell and accidentally fatally shot his father Thursday night in Atoka County.

"At this point, he's saying it's an accident," Atoka County Sheriff Tony Head said.

Sheriff Head said Wyatt Arp, 20, and his father Douglas Arp, 55, were the only ones home Thursday night.

Head said Wyatt told them when he slammed the door of the home it caused a .22 caliber rifle that was leaning up against the wall to fall to the ground and go off. The bullet went straight into his father's chest and killed him instantly.

Wyatt was the one who called 911.

"The 20-year-old son was out in the yard claiming that the gun had fallen and his dad, who was lying on the couch, was struck and killed by the bullet," Head said.

The Oklahoma State Bureau of Investigation was immediately called in to help.

Sheriff Head said he's been out to the house on Bentley Road before and Wyatt is currently on probation for assaulting his father.

"We have had domestics that we've had to respond to that residence in the past, pertaining to this 20-year-old and his father," Head said.

Friends said Douglas Arp grew up in Caney and moved to Atoka recently. News 12 reached out to family and friends, but no one would interview on camera.

While it is possible for a rifle to accidentally go off by hitting the ground, the sheriff said there is more to investigate before the case is closed.

"A loaded gun should not have been in that location to start with and it is still yet to be determined that that is actually the case," Head said.

The sheriff said they are treating the shooting as an accident unless they are proven otherwise.

They are waiting to get the autopsy results from the State Medical Examiner's Office. No one has been arrested.