Sheriff's officials were conducting an underwater search for a second man who may have been involved in a fatal boating accident Sunday morning at Pyramid Lake north of Castaic, authorities said.
One man was confirmed dead earlier Sunday after deputies with the Los Angeles Sheriff's Department parks bureau found him floating near a boat with its bow protruding from the water, according to Deputy Juanita Navarro-Suarez.
Deputies responded to the location after being flagged down around 11:20 a.m. by a man on a jet ski, who reported seeing something near Chumash Island in the southern part of the lake.
Deputies performed CPR on the man, but were unable to revive him. He was pronounced dead at the scene.
The man had no obvious signs of physical trauma and appeared to have drowned, but the exact cause of death has yet to be determined, Navarro-Suarez said.
She said there were no signs of damage to the boat.
Authorities were informed that the deceased boater may have been accompanied by a second man. Divers were called to the scene and underwater searches were continuing into Sunday evening.
Homicide detectives were also present as a matter of protocol, but there was no preliminary sign of foul play, officials said.