Update from the AP at 5:20pm:
A report of a burned pickup truck on a Southern California mountain road is being investigated amid a manhunt for a fired Los Angeles police officer suspected in three murders.
TV news helicopters have shown a helicopter drop a rifle-equipped team onto a mountain near Big Bear Thursday afternoon.
San Bernardino County sheriff's Deputy Zach Beckum says a pickup fire was reported but there has been no sighting of suspect Christopher Dorner. Beckum also says local schools are on lockdown.
A massive manhunt is under way for Dorner, who allegedly killed a former police captain's daughter and her fiance last weekend. He's also suspected of killing a police officer and wounding two others in two separate shootings early Thursday. He was reportedly driving a pickup at the time.
Timeline of Key Events from the AP:
Key events involving Christopher Dorner, the fired Los Angeles police officer suspected of killing at least three people including a police officer in Southern California and posting a manifesto on Facebook outlining plans to kill the families of those he felt wronged him:
- Sunday, Feb. 3: Monica Quan, 28, and Keith Lawrence, 27, are found shot to death in their car at an Irvine, Calif., parking structure. Quan, an assistant women's basketball coach at California State University, Fullerton, was the daughter of a former Los Angeles police captain who represented Dorner in disciplinary hearings that resulted in his dismissal.
- Monday, Feb. 4, about 9:30 a.m. PST: Some of Dorner's belongings, including police equipment, are found in a trash bin in the San Diego-area community of National City, Calif.
- Wednesday, Feb. 6: Irvine police announce they are looking for Dorner as a suspect in the killings of Quan and Lawrence, and say he implicated himself in the killings in a manifesto posted on Facebook. U.S. marshals and other law enforcement officials, acting on a credible lead, search Wednesday night for Dorner in San Diego's Point Loma area.
- Wednesday, Feb. 6, 10:30 p.m.: A man matching Dorner's description tries to steal a 47-foot boat from a San Diego marina, but the engine won't start. An 81-year-old man on the boat is tied up but unhurt.
- Thursday, Feb. 7, 1:30 a.m.: In the Riverside County community of Corona, Calif., two LAPD officers assigned to protect a person named in the manifesto chase a vehicle they believe is Dorner's. One officer is grazed in the forehead during a shootout, and the gunman flees. A short time later, a gunman believed to be Dorner ambushes two Riverside police officers who had stopped at a red light during a routine patrol. One officer is killed and the other critically injured.
- Thursday, Feb. 7, 2:18 a.m.: A shuttle bus driver turns in a wallet with an LAPD badge and a picture ID of Dorner to San Diego police. The wallet is found less than five miles from the boat, near San Diego International Airport.
- Thursday, Feb. 7, 5:15 a.m.: LAPD officers guarding a manifesto target in the Los Angeles suburb of Torrance open fire on a truck they mistakenly believe to be Dorner's. Two women are wounded. A short time later, Torrance police are involved in a second shooting involving a different truck they also mistake for Dorner's. Nobody is hurt.
- Thursday, Feb. 7, 8:30 a.m.: Reports surface that authorities are investigating a burned pickup truck near the Big Bear ski area in the San Bernardino Mountains. A San Bernardino County sheriff's deputy says there have been no sightings of Dorner but local school officials decide to put schools in lockdown.
- Thursday, Feb. 7, 9:30 a.m.: Authorities in central and northern Arizona are alerted about the manhunt for Dorner along with a description of the vehicle he may be driving.
- Thursday, Feb. 7, 9:40 a.m.: Naval Base Point Loma in San Diego is locked down after a Navy worker reports seeing someone who resembles Dorner. Two hours later, Navy officials say they don't believe Dorner was on base.
- Thursday, Feb. 7, 2:30 p.m.: Authorities confirm that the pickup truck found near Bear Mountain ski area at Big Bear Lake belongs to Dorner.
- Thursday, Feb. 7, 3:30 p.m.: San Bernardino County Sheriff John McMahon announces at a news conference that a door-to-door search for Dorner is under way.
Authorities issued a statewide "officer safety warning" and police were sent to protect people named in the posting that was believed to be written by fired officer Christopher Dorner. Among those mentioned were members of LAPD. Urging Dorner to surrender, Police Chief Charlie Beck said Dorner has available multiple weapons including an assault rifle.
The search for Dorner, who was fired from the LAPD in 2008 for making false statements, began after he was linked to a weekend killing in Irvine. One of the victims was the daughter of a former police captain who had represented Dorner during the disciplinary hearing. Authorities believe Dorner opened fire early Thursday on police in area cities, killing a Riverside officer and wounding another.
Beck detailed Dorner's alleged crimes in an usual press conference in an underground room at police headquarters, where extra security was deployed.
"There's no beef that someone can have to kill three innocent people in the way that he has," Villaraigosa said while attending a news conference at the State Capitol where Democratic State Senators unveiled 10 bills they say would reduce gun violence. "So whatever problem he has is mental."
Information from the Associated Press was also used in this story.