SLIPPERY ROCK TWP — Authorities are investigating if a 41-year-old township woman who died Sunday afternoon suffered a medical emergency before her minivan slammed into a tree.

Nicole A. McPherson had no visible injuries when emergency crews found her without a pulse or heartbeat, investigators said.

She was taken to Grove City Medical Center and pronounced dead shortly after the 3:10 p.m. accident in the 200 block of Branchton Road in Slippery Rock Township.

State police said McPherson was traveling east when she lost control of her 2006 Chrysler Pacifica and crossed over the westbound lane on Branchton Road just east of Harmony Road. The van traveled into a home’s front yard and hit the tree head on.

The van ended up between two trees. The homeowner and other motorists who came upon the crash reported that the woman was unresponsive.

The Slippery Rock Volunteer Fire Company and its ambulance crew assisted police.

Investigators said they do not know if McPherson might have had a health issue that caused the accident, or if she possibly died of the medical emergency and any injuries in the crash.

There were no apparent skid marks to indicate that she tried to brake before the van left the road. She was wearing a seat belt.

It was not known if an autopsy was planned. A telephone call to Mercer County Coroner John Libonati was not immediately returned this morning.

McPherson worked for the SGA Bookstore on the Slippery Rock University campus. She was an apparel buyer for the bookstore, which is owned by the Student Government Association.

She had started working there in 1991 while attending high school, said bookstore manager Joe Flynn. In 2004, she was hired full-time in charge of buying clothing merchandise.