BIG BEAR LAKE, Calif. - All that was left were footprints leading away from Christopher Dorner's burned-out pickup truck, and enormous, snow-covered mountains where he could be hiding among hundreds of cabins, deep canyons and dense woods.
More than 100 officers, including SWAT teams, were driven Friday 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 of 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.
"He can be behind every tree," said T. Gregory Hall, a retired supervisor for a special emergency response team for the Pennsylvania State Police. "He can try to draw them into an ambush area where he backtracks."
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 for a suspect bent on revenge and willing to die.
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, ordnance 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 used a search warrant to remove about 10 paper grocery bags of evidence from his mother's single-story house in the Orange County city of La Palma.
The manhunt had Southern California residents on edge. Unconfirmed sightings were reported near Barstow, about 60 miles north of the mountain search, and in downtown Los Angeles.
Their focus was on the mountains 80 miles east of Los Angeles - a snowy wilderness, filled with 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, SWAT teams in camouflage started scouring the mountains.
As officers worked through the night, a storm blew in, possibly covering tracks that had led them away from his truck but offering the possibility of a fresh trail to follow.
"The snow is great for tracking folks as well as looking at each individual cabin to see if there's any signs of forced entry," San Bernardino County Sheriff John McMahon said.
In his online rant, Dorner baited authorities. "Any threat assessments you generate will be useless," it read. "I have the strength and benefits of being unpredictable, unconventional, and unforgiving."