Irvine Police Department
This Jan. 28 image shows Christopher Dorner, police say. It was taken by a surveillance video camera at an Orange County hotel.
Updated at 8:51 p.m. ET: Dozens of police officers went door-to-door in the snowy California mountains on Friday, searching 200 cabins and other buildings for ex-LAPD officer Christopher Dorner, suspected of killing three people in a revenge-fueled rampage he mapped out in an online manifesto.
Meanwhile, investigators released a new image of Dorner and searched the home of Dorner's mother, who police said was cooperating.
The image of Dorner was taken Jan. 28 by a surveillance video camera at an Orange County hotel, police say.
The search was focused on the mountains, where "it's extremely dangerous," San Bernardino County Sheriff John McMahon said at a news conference Friday after more than 100 cops spent a tense night and day patrolling around the town of Big Bear Lake, where Dorner's burned-out truck was found a day earlier.
The search was suspended Friday evening, and was set to resume on the ground at 7 a.m. PT Saturday, NBCLosAngeles.com reported.
Police say Dorner, 33, is on a mission to execute former LAPD colleagues and superiors and their families to avenge his 2008 firing. They believe he murdered a retired captain's daughter and her fiance in Irvine on Sunday, then killed one cop and wounded two others in shootings Thursday.
Chris Carlson / AP
San Bernardino sheriff's Officer Steven Spagon mans a checkpoint during the search for fired Los Angeles officer Christopher Dorner in Big Bear Lake, Calif.
Police followed the tracks until they lost them on frozen ground. They said they have no idea if Dorner is still in the area or if he left the mountain on foot or with a different vehicle.
All night and into the next day, SWAT teams piled into snowcats and armored personnel carriers with snowchains and drove through eight square miles of mountain, checking cabins for signs of forced entry.
"We want to make sure he didn't find a place to hide for the night," McMahon said. "Certainly there has been time to get out of here, but we don't know if he has, in fact, left."
With the heavily armed suspect eluding capture for a second day, schools were closed Friday, though the ski resorts were open.
Credit: Los Angeles Police Dept. newsletter via NBCLosAngeles
This undated photo released by the Los Angeles Police Department shows suspect Christopher Dorner.
“There is no panic,” said Big Bear Mayor Jay Obernolte. “We're very hardy residents…and many people are armed.”
He said his biggest concern was that a gun-toting resident might spot Dorner and try to take him on themselves. He urged everyone to keep their distance from Dorner and call police for help.
The sheriff acknowledged that the hunt for a man who is effectively hunting them could be nerve-wracking.
"This business is not always safe," he said. "But this is what we train for."
Ex-cop's mom, sister cooperating
Friday afternoon, Irvine and La Palma police, joined by U.S. marshals, were at the home of Dorner's mother in La Palma, a small city in Orange County about 20 miles southeast of Los Angeles.
Dorner's mother and sister were at the home and were cooperating, officials told NBC 4 of Los Angeles.
"I knew they were here for something," neighbor David Pighin said. "I thought maybe he was coming back to say goodbye to his mother."
The LAPD believes Dorner, who is 6 feet and 270 pounds, has an arsenal of weapons that includes assault rifles.
Dorner earned a ribbon for rifle marksmanship and a medal for pistol expertise in the Navy Reserve, where he was a lieutenant until his honorable discharge last week. Two bases in Nevada and California where Dorner worked were on heightened security over concerns that he might still have his military ID.;
Dorner worked at Fallon Naval Air Station, Nev., from March to November 2009, Zip Upham, a spokesman at Fallon, told NBC News. He also oversaw some security operations at Stead Air Force Base, Calif.
Dorner previously served in the LAPD from 2005 to 2008 and was fired for making false statements after he accused a training officer of brutalizing a man.
During an internal review, he was represented by Randal Quan, a retired captain. His daughter Monica Quan, 28, and her fiancé, Keith Lawrence, 27, were fatally shot while parking their car at their apartment complex after a Super Bowl party.
In the 11,300-word manifesto, Dorner vented his rage at Quan and other police officials and made it clear he had no compunction about killing their loved ones.
"I never had the opportunity to have a family of my own, I’m terminating yours," he wrote in one chilling passage.
The father of the man who was allegedly roughed up by the training officer told NBCLosAngeles.com that he thought Dorner made too big a deal of the 2007 incident by filing a formal accusation.
“He stood up for what he thought was right,” he said. “You could tell by the look on his face he was just a young, idealistic kid, who was proud of the badge," Richard Gettler said. "I commended him first. Then I got close to him and said, 'What is wrong with you? Weren't you thinking? ... It's the three musketeers, all for one and one for all!'"
Gettler called the recent killings horrible and urged Dorner to turn himself in.
"Back then, when he became a police officer, he wanted to do good," Gettler said.
"This has gone far enough," Beck said Thursday night. "No one else needs to die."
M. Alex Johnson and vivian Kim of NBC News contributed to this report.
- Family at center of Dorner's manifesto urges surrender
- Women shot by cops during manhunt had no warning, lawyer says
The tense search for a former cop who police say killed three people and vowed to murder more continued for a second day. NBC's Miguel Almaguer reports.