Sgt. Shiou Deng, 53, and 34-year-old Jesus Garcia were both killed around 2 a.m. June 23 on the southbound side of the interstate, just north of Moraga Drive.
Deng's funeral was held at Forest Lawn - Covina Hills Mausoleum in Covina.
"Sergeant Deng lived his life the way most of us wish we could -- with kindness, with humor, and with purpose," LAPD Chief Jim McDonnell said, eulogizing the late police officer. "He didn't just do the job, he lifted up people doing it beside him. He made people laugh when they needed it most. He made them feel seen, valued and included."
According to the California Highway Patrol, officers from the agency's West Los Angeles office responded to the southbound freeway just north of Moraga Drive, initially in response to a single-vehicle crash.
"Officers found a Toyota pickup ... disabled in the HOV and No. 1 lanes," according to a CHP statement.
"Shortly after the crash, LAPD Sgt. Shiou Deng arrived in a marked patrol vehicle with emergency lights activated and stopped behind the Toyota, partially blocking the same lanes. As Sgt. Deng exited his vehicle to assist ... a Nissan sedan, driven by Mario Bickham, struck the patrol vehicle and then hit Sgt. Deng."
Garcia, the driver of the Toyota, was standing outside his vehicle and was also struck. He died at the scene. Deng was transported to Ronald Reagan UCLA Medical Center in Westwood, where he was pronounced dead.
Bickham was also taken by ambulance to a hospital, but there was no word on his condition.
LAPD sergeant among 2 killed in crash on 405 Freeway
A GoFundMe page created by Garcia's family described him as "a loving son, brother, uncle, and friend whose kindness and warmth touched everyone he met."
According to LAPD Chief Jim McDonnell, Deng stopped to help.
"He saw that it was a serious crash and he activated his rear amber lights in an effort to be able to slow traffic behind him and provide some level of safety for the people who were involved in that collision," McDonnell said.
McDonnell said the sergeant achieved his current rank two years ago and was assigned to the department's West Los Angeles Division.
"He's an exceptional guy," McDonnell said. "A true leader. A true hero. He had 26 1/2 years on the LAPD. During that time, he spent about 17 of those years working our Mental Evaluation Unit, where he was out there every day caring for the most vulnerable in our society."
City News Service contributed to this report.