An autopsy Friday determined a Thousand Oaks man suffered a fatal heart attack before Mark Parker, 52, was pronounced dead at the scene about 11 a.m. Thursday after his body was falling into Lake Piru with his 13-year-old son, coroner's officials said.
pulled from about 35 feet of water. Parker had taken his son Brett to the lake Wednesday on a Sheriff's officials said Parker collapsed in the boat and landed on the throttle. The boat surprise fishing trip, authorities said.
afloat but was unable to do so. He then flagged down a passing boat.
Sheriff's divers had searched into Wednesday night for Parker before stopping and resuming at 7 a.m. Thursday.