AIKEN, S.C. (AP) — Authorities are investigating what caused a South Carolina man to drive his pickup truck into a ravine in a single-vehicle fatal accident.

Aiken County Coroner Tim Carlton says in a news release that 79-year-old Harold E. Lanier of North Augusta was pronounced dead at Augusta University Medical center after the crash on Saturday night.

The news release says that he was traveling north on a highway near Aiken Technical college when witnesses saw him begin to swerve. His 2002 Chevrolet pickup truck left the road and went down a small ravine, according to the news release.

The coroner says that authorities are trying to determine whether he died from the impact of the accident or was having a medical problem before crashing. An autopsy is scheduled for Monday.