Officials have determined an elderly Cranberry Township couple died of accidental carbon monoxide poisoning.

The bodies of Walter Mullenax, 93, and his wife, Lucille, 89, of North Boundary Road were discovered by a caretaker Friday, Butler County Chief Deputy Coroner John Hanovick said.

Hanovick said he pronounced the couple dead at the scene at 4:30 p.m.

Hanovick said the couple’s vehicle ran unattended in the basement-level garage. He ruled the deaths an accidental carbon monoxide poisoning.

“The car was still running when police got there,” Hanovick said, who arrived after the vehicle had been turned off by police. “They’re older people. It just happened.”

Hanovick said the body of Lucille Mullenax was found in the upstairs hallway, and her husband’s body was found in a chair in the living room.

Hanovick said he did not see or hear any carbon monoxide detectors.

No autopsy is planned.