Graham, N.C. — The search continued Wednesday for a man authorities believe stole a single-engine plane from Horace Williams Airport in Chapel Hill before crashing into a grove of trees about 25 miles away in Alamance County Tuesday.

Investigators did not release the suspect's name, but Sheriff Terry Johnson said two K-9 units followed his track out of the woods, then lost it.

Blood was found in the cockpit, leading authorities to believe that they are looking for an injured man, Johnson said. It wasn't clear whether there were any passengers on the plane.

The search began around 7 a.m. Tuesday when an emergency beacon alerted the Civil Air Patrol, a volunteer service of the U.S. Air Force, to a plane in trouble. The plane was later found off Wildlife Club Road near N.C. Highway 87 around 12:15 p.m.

Johnson said the crash might have happened because the pilot didn't know how to switch gas tanks – one of which was empty – on the aircraft, and it ran out of fuel.

Authorities believe the Piper PA-32R-301T, which is registered to Hillsborough businessman Larry Warren, was stolen sometime between 9 p.m. Monday, when Warren left it at the airport, and 6 a.m. Tuesday. Airport employees are only on site from 6 a.m. to 8 p.m.

Warren said he checked the instrument panel at the crash scene and determined that whoever stole the plane flew for nearly two hours before crashing.

"I record the hours when I get in it and when I get out of it, and it looked like he had flown for 1.9 hours somewhere," Warren said. "I don't know if he was flying around (or) if he went somewhere and was coming back."

He also said that the plane would have easily started up for a thief, once he had broken into it.

Randy Young, a public safety spokesman for University of North Carolina at Chapel Hill, which runs Horace Williams Airport, said this is the first time a plane has ever been stolen there. He said the airport is secure. 

"Because the airport is on UNC property, there is a certain level of security. We do patrols there as we do on the contiguous campus and fringe areas," Young said.

Vehicles can only get in with a security code through a locked gate, but pedestrians have open access to the lots where small, private planes are parked, Young said.

Aviation attorney James Crouse said the security at Horace Williams is the norm for small facilities. He said it surprises him that planes, with their lightweight doors and windows and lack of heavy locks, are not stolen more frequently.

"The aircraft itself is ripe for being broken into," Crouse said. "Aircraft are not made to be secure; they are meant to fly in the air."