Officers arrived to find King in the water and unresponsive, with no signs of foul play. He was transported to Arrowhead Regional Hospital, where he was pronounced dead at 6:11 a.m, Hardin said.
The San Bernardino County coroner will perform an autopsy within 48 hours.
The 1992 riots, which were set off by the acquittals of the officers who beat King, lasted three days and left 55 people dead, more than 2,000 injured and swaths of Los Angeles on fire. At the height of the violence, King pleaded on television: "Can we all get along?"
In an interview earlier this year with The Associated Press, King said he was a happy man.