All that was left were footprints leading away from Christopher Dorner's burned-out truck, and an enormous, snow-covered mountain where he could be hiding among the skiers, hundreds of cabins and dense California woods.
More than 100 law enforcement officers, some in armoured personnel carriers, hunted for the former Los Angeles police officer suspected of going on a deadly rampage this week to get back at those he blamed for ending his police career. Three were dead, including one officer.
With bloodhounds in tow, officers went door to door as snow fell, aware they could be walking into a trap set by the well-trained former US Navy reservist who knows their tactics as well as they do.
"The bottom line is, when he decides that he is going to make a stand, the operators are in great jeopardy," said T Gregory Hall, a retired tactical supervisor for a special emergency response team for the Pennsylvania State Police.
As heavy snow fell in the mountains, thousands of heavily armed police remained on the lookout throughout California, Nevada, Arizona and northern Mexico.
Police said officers 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 Los Angeles Police Department and its families.
The manhunt had Southern California residents on edge. Some law enforcement officials speculated that he appeared to be everywhere and nowhere, and that he was trying to spread out their resources.
The focus was on the mountains east of Los Angeles - a snowy wilderness, filled with deep canyons, thick forests and jagged peaks. Bad weather grounded helicopters with heat-sensing technology.
Property records show his mother owns undeveloped land nearby, but a search of the area found no sign of him.
"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," said San Bernardino County Sheriff John McMahon.
In his online rant, Dorner seemed to taunt authorities.
"I have the strength and benefits of being unpredictable, unconventional, and unforgiving," he wrote.
Authorities said they did not know how long Dorner had been planning the rampage. Even with training, days of cold and snow can be punishing.
"Unless he is an expert in living in the California mountains in this time of year, he is going to be hurting," said former Navy Seal Clint Sparks, who now works in tactical training and security.
Jamie Usera, an attorney who befriended Dorner when they were college students, said he introduced him to the outdoors and taught Dorner about hunting and other outdoor activities.
"Of all the people I hung out with in college, he is the last guy I would have expected to be in this kind of situation," Usera told the Los Angeles Times.
Others saw Dorner differently. Court documents obtained by The Associated Press on Friday (local time) show an ex-girlfriend of Dorner's called him "severely emotionally and mentally disturbed" after the two split in 2006.
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 typically given out as a souvenir by the LAPD police chief was also in the package, riddled with bullet holes.
On Sunday, police say Dorner shot and killed a couple in a parking garage. The woman was the daughter of a retired police captain who had represented Dorner in the disciplinary proceedings that led to his firing in 2008.
According to documents from a court of appeals hearing, Dorner was fired after he made a complaint against his field training officer, saying that said that in the course of an arrest, she kicked suspect Christopher Gettler, a schizophrenic with severe dementia.
Richard Gettler, the schizophrenic man's father, gave testimony that supported Dorner's claim. After his son was returned home on July 28, 2007, Richard Gettler asked "if he had been in a fight because his face was puffy" and his son responded that he was kicked twice in the chest by a police officer.
Hours after authorities identified Dorner as a suspect in the double murder, police believe Dorner shot and grazed an officer and then used a rifle to ambush two police officers early Thursday, killing one and seriously wounding the other.
The incident led police to believe he was armed with multiple weapons, including an assault-type rifle.
Law enforcement officials said they will continue to search for Dorner through the weekend.