SAN DIEGO - Team 10 traced Christopher Dorner's apparent hatred for the Los Angeles Police Department back to a single incident.
In a manifesto posted online, Dorner claimed the LAPD was part of a conspiracy against him.
In October 2007, while Dorner was a patrol officer, court records show he went to a Doubletree Hotel in San Pedro to make an arrest, along with his training sergeant.
The records show she was critical of his work, stating he needed to improve his "common sense" and "good judgment."
The sergeant also questioned the thoroughness of Dorner's reports and how long it took for him to write them.
Court records show Dorner accused the sergeant of kicking a suspect and using unnecessary force. The department's internal investigation determined Dorner made a false statement and fired him.
Dorner sued the department and lost. He appealed, but lost.
In his manifesto posted online, Dorner wrote a lot about his complaint against the department.
"Nothing was done," Dorner said. "I had broken their supposed 'blue line.'"
Through his writing, Dorner appears to have felt disgraced, also writing about his desire to reclaim his name.
Dorner graduated from the police academy in early 2006. His appeal was lost in October 2011.
More than a year later, he would become a man 10,000 law enforcement officials tried to find.
Dorner allegedly began his crime spree with the shooting deaths of Monica Quan, 28, and her fiance, Keith Lawrence.
Quan's father defended Dorner during the LAPD hearings that led to his dismissal.