Christopher Dorner became a cop in 2005 in Los Angeles. The Associated Press reported that In 2008 he was fired from the force, which led him to kill people in a revengeful plot.

The Associated Press reported that Dorner killed a man and his fiance whose father represented Dorner when he fought for his job. Dorner also ambushed two police officers, killing one of them.

Dorner left behind an expansive manifesto that reads, "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. You are saying to yourself that this is completely out of character of the man you knew who always wore a smile wherever he was seen."

Dorner does not have any children and his wife filed for divorce in 2007, reported the AP.  Dorner said he would use his training to avoid track his targets and avoid being captured. He was in the Naval Reserves and received a rifle marksman ribbon and pistol expert medal.

"He served in a naval undersea warfare unit and various aviation training units, according to military records, and took a leave from the LAPD and deployed to Bahrain in 2006 and 2007," reported the AP.

His manifesto read,  "I will utilize every bit of small arms training, demolition, ordinance and survival training I've been given. You have misjudged a sleeping giant."

The AP reported that the manifesto also includes 40 different targets and warned them that he will hurt their families.

"I never had the opportunity to have a family of my own, I'm terminating yours," said the manifesto. The document showcases that racism is a motivation for the revenge.

ABC News reported that Dormer might also have many guns and is believed to have access to military uniforms because of his history in the Navy.

"We are considering him armed and dangerous," Lt. Julia Engen of the Irvine Police Department said to ABC News.

Police believe he was at a yacht club Wednesday night in Point Loma, California to steal a boat. It's believed that he headed to Riverside where he shot two police officers.

"He pointed a handgun at the victim [at the yacht club] and demanded the boat," Lt. David Rohowits of the San Diego Police Department said to ABC News.

"[This is an] extremely tense situation," Sgt Rudy Lopez from the LAPD said to ABC News. "We call this a manhunt. We approach it cautiously because of the propensity of what has already happened."