Authorities were patrolling a mountain resort town in heat-sensing copters and fanning out on foot in fresh snow even as vacationing families and weekend skiers frolicked nearby.
The stark blue skies that emerged after a Friday snowstorm allowed San Bernardino County sheriff's choppers to fly low over the forest and SWAT teams to look for tracks and other clues that might lead to Christopher Dorner, 33, whose burned out pickup truck was discovered Thursday in town.
Authorities suspect Dorner in a series of attacks in Southern California over the past several days that left three people dead, including a police officer. Authorities say he has vowed revenge against several former LAPD colleagues who he believed cost him his law enforcement career.
The intense manhunt Saturday didn't appear to bother the majority of tourists intent on enjoying the perfect winter weather, which made for strikingly odd contrasts: the sound of barking bloodhounds mixed with rap music blaring off the ski slopes; a family with kids strolling by a deputy, who was clad in full tactical gear and practicing his aim on a small snowdrift.
San Bernardino County sheriff's Det. Chad Johnson said he and others were intent on finding Dorner but also looking for other telltale signs of his whereabouts.
"There's a million clues in the mountain. You've just got to be patient to find them," Johnson said.
Johnson said the foot search includes mountainous areas that are very steep and high climbs that often end in cliffs.
"It's a challenging day of work," Johnson said.
The search was the third full day of the massive multi-agency effort now centered on this resort town about 80 miles northeast of downtown Los Angeles. Investigators continue to analyze the burned out truck discovered Thursday on a local road, and are trying and determine whether Dorner torched it or if it caught fire for other reasons.
Officers armed with semi-automatic weapons have been going door to door examining hundreds of vacant cabins, aware that they could be walking into a trap set by the well-trained former Navy reservist who knows their tactics and strategies.
"Christopher Dorner is probably one of the most dangerous fugitives that law enforcement has gone after in recent times," said Clint Van Zandt, former supervisor of FBI's profiling unit. "The challenge is, with his law enforcement and military background; he's very competent with weapons."
Sheriff's Det. Jeremiah MacKay, who began his patrol at 5 a.m. Saturday, said the operation was both massive and tactically complex.
"This one you just never know if the guy's going to pop out, or where he's going to pop out. We're hoping this comes to a close without more casualties. The best thing would be for him to give up," MacKay said.
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.
Dorner served in the Navy, earning a rifle marksman ribbon and pistol expert medal. He was assigned to a naval undersea warfare unit and various aviation training units, according to military records. He took leave from the LAPD for a six-month deployment to Bahrain in 2006 and 2007.
Last Friday was his last day with the Navy and also the day CNN's Anderson Cooper received a package that contained a note on it that read, in part, "I never lied." A coin riddled with bullet holes that former Chief William Bratton gave out as a souvenir was also in the package.
Police said it was a sign of planning by Dorner before the killing began.
On Sunday, police say Dorner shot and killed a couple in a parking garage at their condominium in Irvine. The woman was the daughter of a retired police captain who had represented Dorner in the disciplinary proceedings that led to his firing.
Dorner wrote in his manifesto that he believed the retired captain had represented the interests of the department over his.
Hours after authorities identified Dorner as a suspect in the double murder, police believe Dorner shot and grazed an LAPD officer in Corona and then used a rifle to ambush two Riverside police officers early Thursday, killing one and seriously wounding the other.