A manifesto posted by Dorner on social media declared "unconventional and asymmetric warfare" upon the LAPD, their families and their associates unless the department admitted publicly he was fired in retaliation for reporting excessive force.

According to the Los Angeles Times, Evans said that on Dorner's first day working with her, he told her that he planned to sue the LAPD after he completed his probationary period, in response to how the department had responded to complaints he had previously made against his classmates.

[9] On July 28, 2007, Dorner and Evans responded to the Doubletree Hotel in San Pedro regarding a disturbance being caused by Christopher Gettler, who had schizophrenia with severe dementia.

[18] Additionally, a port police officer testified that he did not see Evans kick Gettler, though some aspects of his statement contradicted photographs from the scene.

[19][27][28] Dorner appealed his termination by filing a petition for a writ of mandamus with the Los Angeles County Superior Court.

[23] Judge David Yaffe wrote that he was "uncertain whether the training officer kicked the suspect or not" but nevertheless upheld the department's decision to fire Dorner, according to the Times.

[23] In early February 2013, coincident with the start of a series of revenge shootings, Dorner was purported to have posted a detailed note on his Facebook page, discussing his history, motivations and plans.

[32][33] Dorner listed forty law enforcement personnel whom he was prepared to kill and stated: "I know most of you who personally know me are in disbelief to hear from media reports that I am suspected of committing such horrendous murders and have taken drastic and shocking actions in the last couple of days", the posting began.

It has gotten worse...."[34][35] Dorner issued a single demand: a public admission by the LAPD that his termination was in retaliation for reporting excessive force.

After the first killings, the threats in his manifesto caused law enforcement to mount a widespread manhunt that spread from California to Nevada and Mexico.

[40][41] Protection details were set up for over forty potential targets of Dorner, and thousands of police were assigned to patrol highways across southern California.

"[20] According to military sources, Dorner checked into Naval Base Point Loma in San Diego, but skipped checkout procedures when leaving.

[14][41] About twenty minutes after the Corona shooting, two officers of the police department in neighboring Riverside were ambushed and shot while stopped in their marked patrol unit at a red traffic light.

One officer, Michael Crain, died shortly after the shooting; the other was rushed to a nearby hospital in critical condition for surgery and survived.

[54] Hours later, the burning remains of Dorner's vehicle, a dark gray 2005 Nissan Titan, were found on a remote fire trail by a local, Daniel McGowan, near Big Bear Lake, about 80 miles (130 km) from Los Angeles.

[61] With Dorner believed to be hiding somewhere in the San Bernardino Mountains, an unmanned aerial vehicle was deployed to aid the search from the air during fears that he would head for the Mexican border.

Authorities also discovered surveillance footage of Dorner purchasing scuba diving gear at a sporting goods store in Torrance.

[65] A message posted to the Twitter account of the San Bernardino County district attorney's office said:[66][67][68][69][70] The sheriff has asked all members of the press to stop tweeting immediately.

[73] On February 12, deputies of the San Bernardino County Sheriff's Department (SBSD) responded to a report of the carjacking of a white Dodge truck at 12:22 pm (PST) and began looking for the vehicle on the ground and from the air.

[74] The SBSD confirmed to the media that Dorner was barricaded in a cabin near the command center set up for the manhunt, in a mountainous rural area northeast of Angelus Oaks, and that the building was surrounded by law enforcement.

[84] That same day, San Bernardino County Sheriff John McMahon disputed rumors that deputies had intentionally burned down the cabin.

[85] On February 14, medical examiners confirmed during an autopsy, using dental records, that the charred body found in the burned-out cabin was in fact that of Dorner.

[86] The following day, the SBSD announced the autopsy showed Dorner died from a single self-inflicted gunshot wound to the head.

SBSD captain Gregg Herbert, who led the assault on the cabin, claimed that the canisters were a last resort, adding that the potential for fire was considered.

[90] At about 5:30 am (PST), at least seven[91] LAPD officers on a protection detail of an unnamed LAPD official's residence in the 19500 block of Redbeam Street[92] in Torrance opened fire on the back of a light blue Toyota Tacoma and shot its two occupants, Emma Hernandez (71) and her daughter, Margie Carranza (47)[91][93] delivering newspapers for the Los Angeles Times.

[101] The LAPD declined to confirm the total number of officers involved or how many bullets were fired or if any verbal warnings were given to the women before the shooting began.

[95] Approximately 25 minutes after that incident, officers from the Torrance Police Department (TPD) opened fire on and struck another vehicle.

[102] Like the first shooting, the incident involved a vehicle that police claimed resembled the description of Dorner's truck, but was later discovered to be a black Honda Ridgeline driven by David Perdue, a white male.

Ultimately the reward was divided four ways, with $800,000 going to James and Karen Reynolds, who were tied up by Dorner in their Big Bear Lake cabin before he stole their vehicle; $150,000 to Daniel McGowan; and $50,000 to R. L.

In their application for a search warrant, investigators claimed Young stated Dorner had obtained firearms, weapons sights, silencers, and high-capacity magazines and intended to sell them online at the Backpage website.