BOULDER, Colo. -- Friends and family said they are still confident they will find a 21-year-old missing Iraq veteran in Eldorado Canyon State Park.

Sunday was the fifth day of searching for Marine Lance Hering. He was last seen on Tuesday.

Nearly 130 searchers made their way down the mountain Sunday evening after a long day of searching for Hering. The search will resume Monday morning.

"It's depressing. It's frustrating," said div. Chief Dennis Hopper with the Boulder Sheriff's Office. "Probably my intent is to at least go through tomorrow."

Friend Steve Powers said Hering was injured in a fall while they were free climbing on a cliff. He went for help and when he came back with rescuers three hours later, Hering was nowhere to be found.

A mountain lion, bear and a rattlesnake have been seen by searchers in the area.

At times more than 100 people have been in the search, aided by a Denver police helicopter.

A division chief with the sheriff's department said with his 32 years experience he believes this is the widest-range, longest running search of its kind.

A pair of socks were found Sunday about one mile away from where Hering was last seen. Searchers said it is a long shot that they belong to him, however.