Upstate authorities are searching for a 21-year-old Summerville High School graduate who disappeared from the Presbyterian College campus this week.

Eric Robertson was last seen inside his dorm at 11 p.m. Monday, Clinton Public Safety Director Stacy Drakeford said.

Police don't suspect foul play at this time, but Drakeford said Robertson has serious health issues that have police concerned. He declined to comment on what those health issues are.

Robertson's car was found on campus, and his belongings appear to be in order.

Authorities so far have searched a three-mile area on the campus and the woods surrounding it. He said they expanded their search Friday to include an area of vacant houses on another side of town.

"Either he's picked up a ride from someone else we don't know about or he walked away," Drakeford said.

Authorities from Laurens County, the S.C. Department of Natural Resources and the State Law Enforcement Division have helped with the search. Drakeford said a Greenville group has volunteered to bring a dog team to search the area again today.

"We're doing all we can do," Drakeford said.

Reach Andy Paras at 937-5589, aparas@postandcourier.com.