(CNN) — (CNN) -- A manhunt is under way for a former Los Angeles police officer and Navy Reserve officer accused of shooting three police officers -- killing one -- and slaying two other people in the past week.
Christopher Jordan Dorner, 33, had threatened to target law enforcement officers in retaliation for being fired more than four years ago, authorities say.
Here's a timeline of the case:
2001-2002: Dorner graduates college, joins Navy
Dorner grew up in Southern California before attending Southern Utah University, where he was a running back for the school's football team. He graduated with a degree in political science in 2001.
He joined the Navy after college, receiving a commission as an ensign in July 2002. He trained in river-warfare units and eventually was rated as a rifle marksman and pistol expert, according to Pentagon records.
2005-2006: Dorner starts LAPD career
Dorner enrolled in the LAPD Academy in February 2005. After graduation, he spent a few months on the streets as a trainee.
2006-2007: In Iraq with the Navy
The Navy recalled Dorner to active duty, and he served a 2006-2007 stint in Iraq guarding oil platforms.
2007-2011: Return to LAPD, termination and appeals
After his tour in Iraq, Dorner returned to the LAPD in 2007. Shortly after his return, he reported excessive force by a fellow police officer in July 2007.
In a letter allegedly written by Dorner and provided to CNN this week, he said he was relieved of his duties in 2008 after he made the report against the other officer. The letter was provided to CNN by an LAPD source after this week's manhunt began.
Dorner tried to get his job back in 2008, but LAPD's Board of Rights rejected his appeal. He eventually took the case to court, but a judge ruled against his appeal in October 2011.
February 1: Dorner leaves Navy
Dorner was honorably discharged from the the U.S. Navy Reserve as a lieutenant, according to Pentagon records.
Sunday: Two killed in Irvine
Two people -- Monica Quan, 27, and her fiance, Keith Lawrence -- were killed in Irvine, California, while sitting in a vehicle at a parking structure, authorities said. Quan was the daughter of former LAPD officer Randal Quan, who, it is claimed in the letter, bungled Dorner's LAPD termination appeal.
Tuesday: Dorner at Navy hotel in San Diego
Dorner on Tuesday checked into the Navy Gateway Inns and Suites on San Diego's massive naval base, according to Navy Cmdr. Brad Fagan. Dorner likely had access to the hotel from having been honorably discharged, which would mean he would have an ID card, Fagan said.
Dorner failed to properly check out of the Navy hotel Wednesday as expected, though he is not believed to still be on base, Fagan said Thursday.
Wednesday evening: Dorner named suspect; police announce threats
Authorities named Dorner a suspect in the Irvine killings. Authorities said he issued a "multipage manifesto" allegedly implicating himself in the slayings and complaining of his treatment in the LAPD.
Police said Dorner made violent threats against Los Angeles police officers. Police assigned officers to protect people connected to the threats.
Wednesday, about 8:30 p.m. PT: Attempted boat theft in San Diego
Investigators said they believe Dorner tried to steal a boat from someone in San Diego, according to the LAPD. Dorner "was not successful, and he fled the location," LAPD Chief Charlie Beck said.
Later, a wallet is found containing Dorner's identification and an LAPD detective's badge near the San Diego airport, according to police.
Thursday, shortly after 1 a.m. PT: LAPD officer shot in Corona
In Corona, California, Dorner fired at Los Angeles police officers who were assigned to protect someone connected to Dorner's threats, police said.
One officer was grazed in the head. The wound was not life-threatening, Los Angeles police said.
The officers returned fire, and Dorner fled, police said. "Due to damage to the police vehicle because of his gunshots, the officers were unable to pursue him," LAPD Chief Charlie Beck said.
Thursday, about 1:35 a.m. PT: Officer killed, another shot in Riverside
Riverside police said two of its officers were shot in an ambush at an intersection. One died, the other was taken to a hospital.
Dorner was named a suspect. Riverside police said they believe Dorner drove up to the officers' vehicle, which was stopped at a stoplight, and fired at the officers with a rifle.
The officer who died, a 34-year-old whose name wasn't immediately released, had been on the Riverside force for 11 years, according to Riverside Police Chief Sergio Diaz.
The other officer, a 27-year-old, was "seriously wounded but we expect a full recovery," Diaz said.
Police learned of the shooting when a Good Samaritan picked up a police radio and made a distress call on behalf of the wounded officers, Riverside police say.
Thursday, about 5:15 a.m. PT: Police shoot two in Torrance in 'mistaken identity'
While searching for Dorner, police shot two people in Torrance in a case of mistaken identity, LAPD Chief Charlie Beck said.
LAPD officers who were assigned to protect someone who "was under the most serious levels of threat" saw a vehicle that looked like Dorner's, Beck said. The vehicle was "driving down the street with the lights turned out," he said.
The officers shot two people in the vehicle, but neither turned out to be connected to the Dorner case, Beck said.
"Tragically, we believe that this was a case of mistaken identity by the officers," Beck said.
Both are taken to a hospital. One was in stable condition Thursday morning with two gunshot wounds, and the other had a minor gunshot wound and was to be released shortly, Beck said.
"I ... feel great sadness for the injuries suffered by ... the two uninvolved citizens in Torrence," Beck said.
Police also shot at another pickup matching the description of Dorner's vehicle in Torrence, but no one was injured in that incident, according to a senior law enforcement source.
Thursday morning: Details of manifesto
An LAPD source gives CNN the manifesto that Dorner allegedly wrote.
In the letter, he allegedly threatened to use his Navy training to harm police officers involved in his case and their families.
"I will bring unconventional and asymmetrical warfare to those in LAPD uniform whether on or off duty," Dorner allegedly wrote.
The letter writer claimed he was terminated after he reported excessive force by a fellow officer, and said his attacks were retribution for his termination, as well as a culture of racism and violence he said continues within the department.
Thursday, 2:30 p.m. PT: Dorner's truck found on fire, police say
Investigators find Dorner's truck abandoned and burning on a forestry road near Big Bear Lake, about 100 miles east of Los Angeles, San Bernardino County Sheriff John McMahon said.