Editor's note: This updates with number of people searching today, belief that if Mr. Leuking is in the park, he's off-trail.

More than two dozen people are on the ground searching Great Smoky Mountains National Park for a Tennessee man whose car was found parked at the Newfound Gap Parking Area, while overhead spotters are looking from a helicopter.

Derek Joseph Leuking, 24, of Louisville, Tennessee, was reported missing by family members and co-workers last Thursday. He was reportedly last seen at 4 a.m. Saturday, March 17 at the Microtell Hotel in Cherokee, North Carolina.

The man's white Ford Escape was located Saturday morning at the Newfound Gap Parking Area in Great Smoky Mountains National Park.  Since that time, rangers have searched more than 40 miles of the Appalachian Trail and other connecting trails radiating out from Newfound Gap, but have not found any conclusive signs of Mr. Leuking.

He was believed to be carrying a dark-colored daypack, but not a tent or sleeping bag for overnight use.

The man is described as a white male standing 5-foot, 11-inches tall, weighing 220 pounds with short brown hair and a short beard. He is believed to be wearing black track pants, white tennis shoes and may have had a Realtree camouflage rain suit.

As of this morning, nearly 30 people were looking for the man.  Search managers now believe that, if he is in the park, he is off-trail.  Three search-dog teams are working the woods along the Appalachian Trail and along an old, abandoned section of U.S. 441 that leaves the parking lot southbound.  A Tennessee Highway Patrol helicopter was assigned to cover the area from the air.

In addition to personnel from Great Smoky Mountains National Park, there were searchers from the Blue Ridge Parkway engaged in the search. Cherokee Tribal EMS had a unit on-scene.  Two dog teams came from the North Carolina Search and Rescue Dog Association and the third came from the South Carolina Search and Rescue Dog Association.

Rangers have also considered that Mr. Leuking may have left the park and are asking anybody who may have seen him since Saturday to contact the park at (865) 436-1230.