Rodney King had been drinking and was on drugs when he plunged into a swimming pool and accidentally drowned in June, a coroner's report has concluded.
Mr King was the black motorist videotaped while being severely beaten by Los Angeles police officers in 1991. The officers' acquittal triggered the devastating 1992 Los Angeles riot.
The report confirmed a previous police conclusion that Mr King died by accident, and the case will be closed, Rialto police Captain Randy DeAnda said.
"It concludes our investigation," he said. "Basically, our investigation revealed the same conclusion and, now that we have the toxicology, it basically reinforces that."
Mr King had fought a long struggle with addiction. A call from his fiancee summoned police to his Rialto home at 5.30am on June 17. Officers pulled him from the bottom of the pool, and he was pronounced dead at a hospital.
Cynthia Kelley told authorities she was in bed when she was woken and saw Mr King at a patio door.
"She described him making grunting and growling sounds and having frothy secretions coming from his mouth," the report stated.
When Mr King fell over a planter, Ms Kelley went for her mobile phone to call for help. She heard a splash and by the time she got to the pool, Mr King was face down in the deep end.
Ms Kelley could not swim and attempted to revive Mr King by prodding him with a pitchfork and hoe before authorities arrived, the report said.
The San Bernardino County Coroner's report listed the cause of death as drowning "and the contributing cause was combined with ethanol (alcohol) and multiple drug toxicity", Capt DeAnda said. Toxicology tests showed that Mr King had a blood-alcohol level of .06 and amounts of PCP, cocaine and marijuana in his system, the captain said.