Police in Rialto, Calif., received a 911 call from King's fiancee, Cynthia Kelly, around 5:25 a.m. Pacific time, Capt. Randy DeAnda told CNN. Responding officers found King at the bottom of the pool, removed him and tried to revive him. He was pronounced dead at a local hospital, DeAnda said.
There were no preliminary signs of foul play, he said, and no obvious injuries on King's body. Police are conducting a drowning investigation,and King's body would be autopsied.
His fiancee heard him in the rear yard, DeAnda said, and found King in the pool when she went outside.
In March of 1991, King was pulled over for speeding after a car chase through Los Angeles. In a grisly scene that a bystander captured on videotape, officers repeatedly struck King with their batons and kicked him while he lay on the ground. Other officers standing nearby failed to intervene.
Although the tape seemed to clearly implicate the police officers, in a subsequent trial they were acquitted. The verdict set off massive racially charged rioting throughout Los Angeles in 1992 -- three of the four officers were white, while King was African American.
The riots that erupted on April 29, 1992, were among worst in American history. By the time order was restored, 53 people were dead, nearly 3,000 people were injured and thousands of businesses were damaged or destroyed.
The following year, a federal jury convicted two of the policemen of a federal charge of violating King's civil rights and sentenced them to 30 months in prison. Two other officers were acquitted. King eventually got a $3.8 million settlement from the city, and the case led to sweeping changes in the LAPD.
The video of King's beating can be seen below: