Searchers intensified their hunt Thursday for a Marine on leave from Iraq who is missing after a fall in Eldorado Canyon State Park near Boulder.
Lance Hering, 21, of Boulder fell Tuesday while free-climbing on a rock face with a friend. The friend said he stayed with him until he regained consciousness and then left to get help.
Hering wasn't there when rescuers arrived.
More than 80 searchers, 60 of which are volunteers, are participating in the hunt for Hering in a five-square-mile area already covered. On Wednesday, searchers concentrated on trails. On Thursday, the area was subdivided into 27 smaller grids, and crews were directed to search individually with "75 percent certainty" before moving on to the next grid.
Searchers told 7NEWS that they were frustrated that they haven't been able to find him so far and that there doesn't seem to be an explanation of why he couldn't be located within the first four hours of the search.
"Something is just not fitting, but they're not sure what," said 7NEWS reporter Dayle Cedars.
Criminal investigators were brought in to investigate Thursday. One detective came down the mountain Thursday afternoon to re-interview family and friends on videotape.
Boulder Sheriff Joe Pelle said there are no indications to believe that what Hering's family and friends have said about his disappearance is not true, but he said something is just not right.
"Well, my son is a very strong young man, and he's injured. He's been injured before and recovered," said Lloyd Hering, the missing man's father. "He could be just a little confused."
Authorities don't believe he hiked out on his own because he would have been spotted by now. Hering had a "substantial" head injury after the fall, rescuers said.
Lightning slowed down the search effort a bit on Thursday because they had to be taken down from the mountain for their safety, 7NEWS reported.
"It has been awhile, but the weather is mild today and there has been some excitement on the part of the dogs in a couple of areas so they can concentrate their search," said Lloyd Hering. "So, my hope is they'll find him and bring him out."
A helicopter will be used to conduct an aerial search of the area.
One searcher said he found the remains of a fresh kill of a mountain lion. Another searcher said she came face-to-face with a mountain lion Thursday. She said the animal jumped out of a bush, spotted her and ran away.
"Our worst fear is that he's up here unconscious and hurt really badly or deceased," said Pelle.
The description of Hering was changed slightly. He is described as being approximately 6 feet 1 inch tall, weighing approximately 180 pounds, with close-cropped brown hair and brown eyes. He was last seen wearing a torn black T-shirt. Searches said a piece of fabric was torn from the shirt to fashion a bandage for his head wound. He was also wearing light-colored, full-length khaki pants and tennis shoes.
Anyone with information to offer is asked to contact the sheriffs office immediately at 303-441-4444.
Teams plan to continue searching for Hering until Saturday, 7NEWS reported.
The rescue groups participating include Rocky Mountain Rescue Group, Boulder Emergency Squad, Front Range Rescue Dogs, Alpine Search and Rescue Group, and the Sheriffs Office Mounted Search and Rescue group.
The sheriff's office said it had sufficient resources available to conduct the search and cannot accept casual volunteers who want to help.
Searchers said a skeleton crew will stay overnight in specific areas of the canyon in case Lance comes out.
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