BIG BEAR LAKE, Calif. - All that was left were footprints leading away from Christopher Dorner's burned-out pickup truck, and an enormous, snow-covered mountain where he could be hiding among the skiers, hundreds of cabins and dense woods.
More than 100 officers, including SWAT teams, were driven in glass-enclosed snow machines and armored personnel carriers to hunt for the former Los Angeles police officer suspected of going on a deadly rampage to get back at those he blamed for ending his police career.
With bloodhounds in tow, officers went door to door as snow fell, aware to the reality they could be walking into a trap set by the well-trained former Navy reservist who knows their tactics and strategies as well as they do.
"The bad guy is out there, he has a certain time on you, and a distance. How do you close that?" asked T. Gregory Hall, a retired tactical supervisor for a special emergency response team for the Pennsylvania State Police.
"The bottom line is, when he decides that he is going to make a stand, the operators are in great jeopardy," Hall said.
As authorities weathered heavy snow and freezing temperatures in the mountains, thousands of heavily armed police remained on the lookout throughout California, Nevada, Arizona, and northern Mexico.
Police said officers still were guarding more than 40 people mentioned as targets in a rant they said Dorner posted on Facebook. He vowed to use "every bit of small arms training, demolition, ordinance and survival training I've been given" to bring "warfare" to the LAPD and its families.
At noon, police and U.S. marshals accompanied by computer forensics specialists served a search warrant on his mother's house in the Orange County city of La Palma. Dorner's mother and sister were there at the time, and a police spokesman said they were cooperating.
The manhunt had Southern California residents on edge. Unconfirmed sightings were reported near Barstow, about 60 miles north of the mountain search, at Point Loma base near San Diego, and in downtown Los Angeles.
Some law enforcement officials speculated that he appeared to be everywhere and nowhere, and that he was trying to spread out their resources.
For the time being, their focus was on the mountains 80 miles east of Los Angeles - a snowy wilderness, filled with deep canyons, thick forests, and jagged peaks, that creates peril as much for Dorner as the officers hunting him. Bad weather grounded helicopters with heat-sensing technology.
After the discovery of his truck Thursday afternoon, SWAT teams in camouflage started scouring the mountains.