US police hunting a former cop accused of killing three people searched a series of abandoned mountain cabins on the slopes above a snow-bound ski resort, at the center of a massive manhunt.
But while the focus of the search remained on the resort of Big Bear, there was also a major lockdown in Los Angeles after a reported sighting not far from the LA Police Department (LAPD) headquarters.
More than 100 officers have been searching in the mountains since Thursday for Christopher Dorner, 33, who threatened in a chilling online manifesto to kill police and their families in revenge for his sacking five years ago.
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The manhunt for Dorner -- described as armed and "extremely dangerous" -- continued through the night and into a second day in and around Big Bear, two hours east of Los Angeles, after his burnt-out car was found in nearby woods.
San Bernardino County Sheriff John McMahon said the focus Friday was on cabins in the mountain area above the resort. "We want to make sure he didn't find a place to hide out for the night," he told reporters.
"There are over 200 cabins up in those mountains that are abandoned or vacant and we're checking those one by one," he added.
He declined to comment on suggestions that Dorner -- a naval reservist and reportedly a trained sniper -- may have deliberately burned his car to lure police or create a false trail while he found some other way off the mountain.
California authorities launched a massive manhunt Thursday for Dorner, suspected of killing a couple on Sunday, before ambushing two policemen early Thursday, killing one. He also injured another officer in a separate incident.
In an Internet manifesto threatening police and their families, former LAPD officer Dorner pledged to "bring unconventional and asymmetrical warfare to those in LAPD uniform whether on or off duty."
The LAPD, backed by agencies including the FBI, is protecting over 40 possible targets, some of them identified in the "rambling" online manifesto by Dorner, a US Navy reservist.
There have been multiple reported sightings in the last two days, but none confirmed so far.
On Friday. police in downtown Los Angeles scrambled after a reported sighting of Dorner near the Twin Towers jail, not far from LAPD headquarters, which has been under heightened security since the manhunt was launched.
Roads were closed off and helicopters searched from overhead, but the lockdown was called off after an hour or two.
Dorner's wallet and an ID badge were found on Thursday in San Diego, two hours south of Los Angeles, police said, while there were also reports of police searches in neighboring Nevada, where he has a house near Las Vegas.
In Big Bear, McMahon said he was confident that footprints leading away from the burnt-out truck were Dorner's.
"They did lead around in that wooded area where the truck was found. We continued to follow them until we lost them where the ground got frozen. We couldn't continue to track," he said.
Dorner posted his manifesto online Monday, saying he was not afraid to die because he had already in effect died when he was dismissed in September 2008 for making false statements about his training officer.
"Suppressing the truth will (lead) to deadly consequences for you and your family. There will be an element of surprise where you work, live, eat and sleep," he said.
Dorner is described as black, six feet (1.80 meters) tall and 270 pounds (120 kilograms) in weight.
While Big Bear schools remained closed Friday, the nearby ski area opened again after shutting down Thursday afternoon.
"We have been assured that the suspect does not pose a substantial threat to the ski resorts or the surrounding community," said the town's mayor, Jay Obernolte.
