Authorities are investigating the weekend death of a 39-year-old Butler County man following a vehicle crash in Forest County.

But state police do not believe Lawrence E. Treadway Jr., of Connoquenessing Township, died of injuries in the crash around 6:40 a.m. Sunday in Tionesta.

“We really don't know why he died,” Forest County Coroner Norman Wimer said Tuesday. “The cause and matter of death are undetermined.”

An autopsy is planned Thursday by Dr. Eric Vey, Erie County's forensic pathologist.

Investigators said Treadway was driving south on Route 62 near the Tionesta State Fish Hatchery when his 1999 Ford-150 pickup went off the right side of the road and struck a utility pole. The cause of the wreck was unknown.

The truck sustained only minor to moderate damage, and the airbags did not deploy. Treadway was not wearing a seat belt.

He still was alive when a Tionesta Ambulance crew arrived, authorities said, and he was able to speak until he blacked out.

Medics took Treadway to an ambulance and performed cardiopulmonary resuscitation. They were headed to a hospital when he died.

Forest County Chief Deputy Coroner Cody Magill was called to the Forest County Visitor Center on Elm Street in Tionesta, where he pronounced Treadway dead around 7:40 a.m. in the ambulance.

According to police investigators, Treadway died shortly after the wreck, “but it is believed the crash was not the cause of death.”

Wimer said there were “no outward signs of injuries” that would cause Treadway's death, and that the trauma from the wreck appeared to be minor. He described the injuries as being scrapes and abrasions, “but nothing significant.”

Authorities said they found no evidence of alcohol or drugs at the scene.

Investigators spoke to family members, who did not know why Treadway was in Forest County, and authorities did not believe he suffered any health problems or medical condition that could explain his death.