On Feb. 3, 2013, Dorner began a murderous rampage, starting with the fatal shooting of Monica Quan and her fiancé Keith Lawrence in the parking structure of their Irvine apartment.
Quan was an assistant basketball coach for Cal State Fullerton's women's basketball team. Lawrence was an officer with USC's Department of Public Safety. The couple was targeted because Quan's father represented Dorner during his dismissal proceedings from the LAPD.
USC officers visited the couple's graves, wearing black bands over their badges.
"This is a very difficult day for USC Public Safety," said Deputy Chief David Carlisle.
The couple met at Corcordia University, where they both played basketball. They got engaged one month before becoming the first of Dorner's victims.
"It made no sense at all. Robbery wasn't the motive," Carlisle said.
In his rambling manifesto, Dorner threatened to wage unconventional warfare against LAPD officers and their families. He ambushed two Riverside police officers on Feb. 7, 2013, killing Riverside Police Officer Michael Crane and wounding the other officer.
Dorner hid out in Big Bear for several days, but he was soon discovered. He made a run for it, fleeing to a remote cabin in the San Bernardino Mountains. During a shootout with officers, Dorner killed San Bernardino Sheriff's Deputy Jeremiah McKay.
While holed up in the cabin, investigators say Dorner shot and killed himself.
"Even though it's a year later, it's still a big loss for the USC Public Safety family," Carlisle said. "He was a fine young man with a great career ahead of him, and we're not going to forget him."
LAPD Chief Charlie Beck tweeted, "One year ago today...we remember the lives of two innocent victims taken from us too soon."