Authorities suspect a pan of grease left unattended on the stove caused a fatal weekend fire at a Butler home.

Paul Josef Jarvis, 22, who lived with his father at the two-story house in the 300 block of First Street, died in the fire shorty after midnight Saturday.

Investigators believe Jarvis, a sophomore at Butler County Community College, was killed when he retuned to the burning home to rescue his pets.

An autopsy was conducted Saturday but a cause of death is pending a toxicology report, according to Butler County Deputy Coroner Larry Barr.

Jarvis likely died of smoke inhalation, Barr said.

Butler police said Jarvis apparently had been cooking with hot grease, possibly french fires, when the fire ignited in the kitchen, which is in the rear of the house.

The fire quickly got into the wall and traveled up the second floor and into the roof, said Butler Fire Chief Nick Ban.

Jarvis’ father, Paul Donald Jarvis, was not home. The elder Jarvis owns the house. He’s lived there since 2005, authorities said.

Trooper Luke Nelson a state police fire marshal, is investigating the cause.

He said it appears to be a cooking fire; however, the condition of the house was too unsafe to conduct a thorough investigation immediately after the fire.

Nelson said he hoped to return to the home in a day or two.

“At this point,” he said, “everything appears to point to an accidental fire.”