SAN DIEGO - Authorities mounted intensive manhunts in San Diego and statewide Thursday for a former Los Angeles police officer suspected of murdering three people, including a police officer, in the Irvine and Riverside areas while on a quest for revenge against despised former rivals in law enforcement.
KEY EVENTS: Search for Christopher Dorner
IMAGES: Incidents linked to Christopher Dorner
Police and military personnel locked down and searched Naval Base Point Loma and a motel on the grounds of the station Thursday morning after someone reported seeing a man matching the description of 33-year-old Christopher Jordan Dorner in the area.
No suspect was found, and authorities decided the sighting likely was not valid, though Dorner apparently had stayed at the inn earlier in the week, SDPD Capt. Terry McManus told reporters during a midday briefing.
"We are still vigorously working with all authorities to get him into custody," McManus said.
U.S. Navy officials confirmed Dorner checked in to the Gateway Inn & Suites Tuesday. He was supposed to check out on Wednesday morning, but he did not.
On Thursday afternoon, a 2005 Nissan Titan pickup truck used by Dorner was found burning in a wooded area near Big Bear, according to the San Bernardino Sheriff's Department. Dorner was nowhere to be found and he remained at large as of 5 p.m.
In a briefing early Thursday evening, authorities said tracks were found near the truck but they "did not lead to a suspect."
Because of the search for Dorner, all schools and facilities in the Bear Valley Unified School District were locked down. Assistant Superintendent Walter Con said in an online message that district officials did not believe there was any immediate danger, but the lockdown was initiated as a precaution.
Additionally, Bear Mountain resort was closed for the remainder of the day due to the law enforcement activity.
"We are in constant contact with federal and local authorities regarding this situation," said Chris Riddle, vice president of marketing at Big Bear Mountain Resorts. "We felt it was in the best interest of the search to close Bear Mountain for the rest of the day."
TV news helicopters showed a helicopter drop a rifle-equipped team onto a mountain near Big Bear Thursday afternoon, the Associated Press reported.
The search for Dorner was also extended to Nevada, as Las Vegas police, the Nevada Highway Patrol, FBI and U.S. marshals are searching for him and his vehicle on Interstate 15 and other southern Nevada roads, according to the AP.
In San Diego, authorities had begun actively looking for the suspect about 2:30 a.m. Thursday, after an LAPD badge and wallet containing his identification were found along Harbor Drive, near Lindbergh Field.
Roughly four hours earlier, a gun-toting man matching Dorner's description boarded a 47-foot yacht docked off Qualtrough Street in the Shelter Island area, tied up an 81-year-old occupant and made a failed attempt to pull the vessel out of its slip. The intruder then stole some things from the man and left.
National City police told 10News that they found property believed to belong to Dorner.
Anyone encountering Dorner should consider him armed and "extremely dangerous" and should not approach or try contacting him but instead call 911 immediately, officials said.
The San Diego police captain urged anyone spotting Dorner -- photos of whom have been broadcast frequently by local and national television news outlets -- to stay well away from him and make an immediate emergency call.
"We ask the community not to get involved beyond dialing 911," McManus said.
As the desperate manhunt for Dorner continues, Team 10 looked at the Internet posting he made before he allegedly began the shooting spree. The LAPD's elite Metropolitan squad was sent to protect people mentioned in the manifesto.
Read More: Full copy of Dorner's manifesto
Riverside police officer killed in shootings
A Riverside police officer was shot to death Thursday and one was wounded by a gunman believed to be Dorner. The gunman, who fled after the shooting in Riverside, ambushed the two officers while they were stopped at a red light, said Riverside police Lt. Guy Toussaint, adding that the two were on patrol and not searching for Dorner.
The wounded Riverside officer was undergoing surgery Thursday morning, Toussaint said.
Before the Riverside shooting, a shooting in Corona also believed to have involved Dorner left a Los Angeles police officer with a graze wound, but his partner was not hurt, police said. The two officers are assigned to the Los Angeles Police Department's Newton Station, said Newton Station Sgt. Ike Ornelas.
Dorner, a U.S. Navy reservist whose last known address was in the 4900 block of Sharon Drive in La Palma.
Dorner is black, 6 feet tall and about 270 pounds. He has been driving a gray 2005 Nissan Titan pickup, California license plate 7X03191, authorities said. At a briefing this morning, police said Dorner apparently had switched license plates, possibly to a plate reading 8D83987 or 8D83997.
Dorner was being sought by Irvine police, Los Angeles police, the FBI and U.S. Marshals Service. He may be anywhere between Los Angeles and San Diego, Maggard said.
Anyone encountering Dorner should consider him "armed and extremely dangerous" and should not approach or try contacting him but instead call 911 immediately, according to the LAPD.
A tip line has been established, (949) 724-7192.
10News learned that LAPD officers will not be on motorcycles Thursday and will be in groups of two. LAPD will continue to give updates throughout the day.
Los Angeles police say officers guarding a person believed to be targeted by Dorner, shot and wounded multiple people in Torrance who were in a pickup.
LAPD officials said the officers were deployed in response to Dorner's written threats to department officials in a rambling 14-page online manifesto.
Police did not say how seriously the people in Torrance were injured, and LAPD Chief Charlie Beck said the shootings were "a case of mistaken identity by the officers."
LAPD officials later determined Dorner was not involved in the Torrance shootings.
2 found dead in Irvine garage
Dorner was represented in the hearing that resulted in his firing by Randy Quan, the father of Monica Quan, who was found dead with Keith Lawrence on Sunday, Irvine Police Department Chief David Maggard said Wednesday.
Dorner posted a multi-page manifesto online Monday, saying he didn't mind dying, because he died when he was fired from the LAPD, Maggard said.
Dorner blamed Randy Quan, a retired Los Angeles Police Department officer, for his firing.
"I never had the opportunity to have a family of my own ... (so) I am terminating yours," Dorner wrote to Randy Quan.
The LAPD's elite Metropolitan squad was sent to protect others mentioned in Dorner's manifesto.
The LAPD issued a statement Wednesday declaring that it was taking the threats "very seriously," implementing "all measures possible to ensure the safety of our LAPD personnel, their families and the Los Angeles community, and will continue to do so until Dorner is apprehended and all threats have been abated."
Dorner worked as a police officer from Feb. 7, 2005 until Sept. 4, 2008, "when his employment was terminated," police said.
Police who received a call at 9:10 p.m. Sunday about a person slumped over in a parked car at 2100 Scholarship found the recently engaged couple dead in Lawrence's Kia, which was parked at the top of the five-story structure for the building where they lived.
There was no evidence Lawrence and 28-year-old Monica Quan were being robbed, said Irvine police Lt. Julia Engen, who noted that the high-density residential community is highly secure with key card access only.
Irvine had two slayings in both 2011 and 2012, according to Engen, who said overall violent crime is at "historic lows" in the city.
Monica Quan was in her second season as an assistant coach for the Cal State Fullerton women's basketball team after holding a similar position at California Lutheran University in Thousand Oaks.
The couple met while at Concordia University in Irvine, where they both played basketball. Lawrence was seeking a career in law enforcement, which made him a good match for Monica Quan because her father was an LAPD officer, friends said.
The 27-year-old Lawrence, who graduated from the Ventura County Sheriff's Academy, was working as a patrol officer at USC's Department of Public Safety. He joined the department in August, said Carl Marziali, USC's assistant vice president of media relations.
Monica Quan was a star athlete at Walnut High School, then played at Cal State Long Beach from 2003-05 before transferring to Concordia University, where she graduated in 2007 with a degree in exercise and sports science. She received a master's degree from Concordia in 2009.
Autopsies on the bodies of Lawrence and Monica Quan were completed Tuesday and Wednesday, respectively, said Jim Amormino of the Orange County Sheriff's Department.
"The coroner determined that both died of multiple gunshot wounds," Amormino said. "No further information will be released at this time."