California police launched a massive manhunt Thursday for a former cop accused of killing three people, including another officer, and posting chilling threats to kill more.
Amid a flurry of reported sightings of Christopher Dorner, 33, authorities put a ski resort east of Los Angeles on lockdown after a vehicle resembling his pickup truck was found burnt out in a mountainside forest.
It also emerged that Dorner had sent a package to CNN presenter Anderson Cooper, with a note, a DVD, and "a coin shot thru with bullet holes," the news anchor said on Twitter.
In an Internet manifesto threatening police and their families, Dorner had warned about "terminating" a retired policeman he blamed for his sacking five years ago and called lesbians and Asians "high value" targets.
"I will bring unconventional and asymmetrical warfare to those in LAPD uniform whether on or off duty," he said.
The LA Police Department, backed by agencies including the FBI, said it was protecting over 40 possible targets, some of them identified in the "rambling" online manifesto by Dorner, a 33-year-old US Navy reservist.
"Dorner is considered to be armed and extremely dangerous," LAPD chief Charlie Beck told a press conference, adding that the suspect has "multiple weapons at his disposal, including assault rifles."
"The criminal with whom we are dealing has made it clear that he considers police officers and their families fair game," added Sergio Diaz, police chief in Riverside, east of Los Angeles, where one officer was killed.
In a flurry of apparent false alerts, a naval base near San Diego was put on lockdown after a possible sighting and an attempt to steal a boat nearby, prompting speculation Dorner planned to flee by sea to Mexico.
Dorner's wallet and an ID badge were found overnight in San Diego, two hours south of Los Angeles, police said, while there also reports of police searches in neighboring Nevada, where he has a house near Las Vegas.
A few hours later authorities in the mountain resort of Big Bear, two hours east of Los Angeles, put schools and a ski area on lockdown after a car matching the description of Dorner's was found in a nearby wood.
TV pictures showed armed police apparently fanning out across a mountain slope, although the LAPD quickly asked broadcasters not to show live footage, to avoid giving Dorner help if he was monitoring the media.
Dorner was already wanted over the suspected revenge killing on Sunday of a couple, Keith Lawrence and Monica Quan, who was the daughter of Randy Quan, a retired police officer he blamed for his firing.
Then he allegedly attacked two other officers overnight in Riverside, killing one and injuring the other. Another officer was injured in a separate incident in nearby Corona.
In addition, two civilians were injured early Thursday when police officers opened fire on them in a vehicle they believed to be Dorner's.
Dorner posted his manifesto online Monday, saying he was not afraid to die because, he said, he had already died when he was dismissed in September 2008 for making false statements about his training officer.
"I never had the opportunity to have a family of my own, (so) I am terminating yours," he wrote to Randy Quan.
"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, referring to Quan and several others.
Dorner is described as black, six feet (1m80) tall and 270 pounds (120 kilos) in weight. He was said to be driving a gray Nissan Titan pickup, and may have changed the license plates.
LAPD chief Beck said Dorner's police and military training made the threat all the more serious. "He knows what he's doing. We trained him ... he's also a member of the armed forces," he said.
"It is extremely worrisome and scary." Asked what message he wanted to give Dorner, he said: "I would tell him to turn himself in. This has gone far enough.
"Nobody else needs to die."