Authorities say an elderly man the family allowed to live on their property shot and killed the victim, identified as William Kelley. Deputies arrested Foster Fletcher, 78. 

Owasso ambulance crews tried to revive the 42-year-old Kelley, whose body was found outside a white metal shop located near the home. They could not save him. 

Foster was booked on a complaint of first-degree murder.

Kelley's son said he and his father went out to the shop to get equipment to retrieve a four-wheeler that had gotten stuck in the mud. They encountered Fletcher, who did not seem to recognize them, although they told the elderly man what they were there for, an arrest report states.

The elderly man went inside the shop saying he was calling police then shot Kelley, deputies say. 

An arrest report says when the first deputy arrived he found Kelley's body and Foster standing nearby holding a rifle. There was a .22-caliber shell casing on the floor.

"Fletcher was taken into custody and stated he shot the man," the report states.

The report also states that there had been a previous incident involving Fletcher in March of this year. The elderly man had appeared confused during that incident and pulled a gun on a man. He'd lived on the property for 10 years, the arrest report states.

Neighbors who spoke with News On 6 say Fletcher was a guardian of the neighborhood and basically a part of the family that took him in.

They say Fletcher helped keep an eye out for burglars because of a recent rash of break ins. They say they are shocked and saddened about what and believe it was a tragic accident.

Kelley's official cause of death will be determined by the medical examiner, Major Shannon Clark of the Tulsa County Sheriff's Office said in a news release.

Owasso police and firefighters and Turley firefighters assisted in the response to the homicide.