LOS ANGELES (Reuters) - Police released a recording on Tuesday of the frantic emergency 911 call placed by Rodney King's fiancée after she found him submerged at the bottom of his swimming pool, but the tape shed little if any light on the circumstances of his death.

King, 47, whose videotaped beating at the hands of Los Angeles police led to racially charged riots two decades ago and sweeping law enforcement reforms in the city, was pulled from his backyard pool early on Sunday, the victim of an apparent drowning.

Police in Rialto, California, a San Bernardino County suburb about 50 miles east of Los Angeles, have said they found no initial signs of foul play or suicide, nor any outward indications that drugs or alcohol were a factor.

But detectives and medical examiners continued their inquiry into the central mystery of how a man who was by all accounts an avid swimmer could have drowned in his own pool.

The county coroner's office conducted an autopsy on Monday, but authorities said they would have nothing more to say on the case until they obtain findings from toxicology tests and tissue studies performed on King's body.

Those results are expected to take several weeks.

In the meantime, Rialto police said they decided that releasing the 911 tape was in the public best interest.

On the tape, which runs for about 5-1/2 minutes, King's fiancée, Cynthia Kelly, who lived with him at his house in Rialto, sobs hysterically as she repeatedly pleads on the phone with the emergency dispatcher to send help quickly.

"He's not moving, he's at the bottom of the swimming pool. ... Please hurry up. Oh, my God," Kelly says.

At one point, Kelly tells the operator she had been sleeping "and all of a sudden I heard something fall, like the table, and then I looked over, and then I went to find him."

FIANCEE TRIED TO 'WAKE HIM UP'

Inexplicably, Kelly is also heard telling the operator several times, "I tried to wake him up," but it was not clear whether she meant that she attempted to awaken King before he ended up in the water, or after.

According to earlier police accounts, Kelly told investigators that shortly before the drowning she had been inside the house talking to King through a sliding glass door that leads the pool area, and that she ran outside when she was alerted by the sound of a splash.

As she can be heard saying to the emergency dispatcher on the tape, Kelly told police she did not jump in after him because she is a poor swimmer.

The Los Angeles Times has quoted a next-door neighbor as saying she heard a man, apparently King, sobbing in his backyard in the hours before the pre-dawn death and also had heard Kelly pleading with him to come back into the house.

The death of King, who was black, came two months after the 20th anniversary of Los Angeles riots triggered by the acquittal of four white police officers criminally charged in his beating a year earlier. The case came to light when a videotape of the confrontation recorded by an onlooker was widely replayed on television and the Internet.

In the midst of the civil unrest that left 53 people dead and caused more than $1 billion in property damage, King famously appealed for calm in a televised appearance in which he asked rhetorically, "Can we all get along?"

Two of the four white officers involved in the beating were later convicted of federal charges in a separate trial and sentenced to 30-month prison terms. A civil jury awarded King $3.8 million in damages.

King, who long struggled with drug and alcohol abuse, financial difficulties and legal problems, recently published a memoir entitled "The Riot Within: My Journey from Rebellion to Redemption."