By Nichola Groom

LOS ANGELES (Reuters) - A former police officer, accused of a vendetta-driven rampage against law enforcement, blames the Los Angeles police for many woes: his firing from the force, the end of his military career, and racism he says he encountered while employed by the police.

This week, Christopher Dorner's anger over those perceived slights turned deadly, according to authorities who accuse him of gunning down five people, killing three, and sparking a massive manhunt across a large swathe of Southern California.

In an online manifesto, the 33-year-old Dorner portrayed himself as a victim who was fired by the LAPD in 2008 for reporting a superior officer's use of excessive force while handcuffing a suspect the previous year.

"The LAPD has suppressed the truth and it has now lead to deadly consequences," he wrote in a document that contained the subject line: "Last resort."

Dorner accused his field training officer of kicking a suspect outside a hotel twice in the shoulder and once in the face after he had been "tased" twice and subdued, according to court papers that were part of a failed attempt to get his job back.

Dorner also said the officer told him not to tell anyone about the incident, which occurred in his first month back after being deployed overseas with the Navy, according to court papers.

But the police department's internal complaint board found no evidence the kicks occurred, partly because hotel employees who witnessed the scuffle said they never saw the officer kick the suspect.

The board instead found Dorner had a motive to falsely accuse his training officer, having been told to improve his performance.

He was fired for making false statements in 2008. He said in his manifesto that he was singled out by the LAPD for breaking "their supposed 'Blue Line.'"

DETERIORATING RELATIONSHIPS

Dorner, who once played football for Southern Utah University, blamed the police department not just for firing him but also for the end of his Navy career and the loss of close relationships.

He listed other grievances as well, such as encountering racism both at the LAPD and as an African-American boy growing up in Southern California.

"I lost my position as a Commanding Officer of a Naval Security Forces reserve unit ... because of the LAPD. I've lost a relationship with my mother and sister because of the LAPD," he wrote. "In essence, I've lost everything because the LAPD took my name and (k)new I was INNOCENT!!!"

While the downward spiral of his professional life was evident, it was not entirely clear what led to the violence nearly five years after his firing and three years after his petition to be reinstated to the LAPD was denied by a judge.

Crystal Lancaster, a neighbor in the Los Angeles suburb of La Palma, where Dorner went to high school and his mother still lives, described him to CNN as "a nice, friendly guy, easy to approach."

Dorner was discharged as a Naval reservist on Friday, two days before the bodies of Monica Quan and Keith Lawrence were found in a car in a parking structure in Irvine, California. The Navy did not give a reason for Dorner's discharge.

Quan is the daughter of a retired LAPD officer who represented Dorner in a hearing that led to his firing from the force.

"I never had the opportunity to have a family of my own. I'm terminating yours," Dorner wrote.

He was identified by police as a suspect in the killings on Wednesday, and was suspected of shooting at police in two incidents in Riverside County on Thursday, killing one and wounding two others.

Dorner earned a degree in political science with a minor in psychology in Utah in 2001, a university spokeswoman said. The next year, he joined the Navy, where he earned awards for marksmanship and a medal for service in the Iraq war.

He was hired by the LAPD in 2005, and received a two-day suspension for accidentally firing a gun at the Police Academy. He was called back to active duty with the Navy and spent six months in Bahrain in 2006 and 2007.

(Additional reporting by Brandon Lowrey in Los Angeles; Editing by Cynthia Johnston and Lisa Shumaker)