King, 47, was found dead in the swimming pool at his Rialto, California, home on Sunday.
A preliminary autopsy report will not be released, a San Bernadino County, California, coroner's spokeswoman Jody Miller said yesterday.
The coroner will wait until a full report, based on the toxicology exam findings, is available in six to eight weeks, Miller said.
There were no preliminary signs of foul play and no obvious injuries on King's body, Captain Randy De Anda said. Police are conducting a drowning investigation, he said.
Rialto police received a 911 call from King's fiancee, Cynthia Kelly, De Anda was quoted as saying by CNN.
Responding officers found King at the bottom of the pool, removed him and performed cardiopulmonary resuscitation until paramedics arrived. He was pronounced dead at a local hospital, police said.
King, whose beating by Los Angeles police in 1991 was captured on videotape and broadcast worldwide, sparked riots after the acquittal of the four officers involved.
Kelly, who was a juror in King's lawsuit against the city of Los Angeles in 1994, told police that King was an "avid swimmer" but that she was not, De Anda said. She said the two had just had a conversation and she went inside, but came back out after hearing a splash and saw him at the bottom of the pool.
De Anda said he did not see any drug paraphernalia "or anything that would indicate that Mr. King was intoxicated" at the scene.
Nearly a year after the rioting in Los Angeles, the four officers stood trial in federal court on civil rights charges. Two were found guilty and sentenced to 30 months in prison, and two were acquitted. King also sued the city of Los Angeles and was awarded USD 3.8 million in damages.