MANNFORD, Okla. (AP) — A Tulsa-area man shot and killed his neighbors before turning the gun on himself in front of police officers who pleaded for him to lower the firearm that he had pointed at his head, police said.

The Oklahoma State Bureau of Investigation said 57-year-old Mary Milam and 59-year-old Donald Langdon were shot to death Monday morning in Mannford, The Tulsa World reported Tuesday.

Upon arriving at the scene, officers found Milam and Langdon dead in their home. Soon after, 83-year-old James Hancock walked out of his nearby mobile home, sat down in a lawn chair and put a gun to his head, Mannford Police Chief Jerry Ridley said.

Hancock told the officers that he had shot Milam and Langdon, the bureau said in a news release.

Responding officers and two investigators from the district attorney’s Drug Crime Task Force tried to convince Hancock to lower his gun, Ridley said. Though he initially complied, he eventually shot himself, Ridley said.

Hancock was pronounced dead at a hospital.

Investigators are uncertain what prompted the confrontation that led to the shooting, Ridley said.

The Mannford police department requested the OSBI’s help with the probe. The last homicide in Mannford took place in 2012, and before that in 1996. The small city of little more than 3,000 residents is 20 miles (32 kilometers) west of Tulsa.

“We don’t have a lot of homicides in Mannford,” he said. “Thank goodness. We can certainly do without.”