DECATUR, Ark. (AP) — A 71-year-old man was fatally shot by a northwest Arkansas sheriff’s deputy who found him driving a tractor and displaying a handgun, authorities said.

Nelson Amos was fatally shot Saturday by a Benton County sheriff’s deputy, according to Arkansas State Police. State police said Sunday that they were investigating the shooting.

State police said that sheriff’s deputies had been called after someone reported hearing gunfire on Amos’ property. State police said that when a deputy later encountered Amos driving a tractor on a local road and brandishing a handgun, the deputy fired his rifle, killing Amos.

State police said their investigation will be submitted to the Benton County prosecutor, who will determine whether the use of deadly force by the sheriff’s deputy was consistent with the law.