A whale fatally attacked an animal trainer at SeaWorld in Florida on Wednesday, jerking her into the pool and thrashing her around underwater as dozens of horrified tourists watched.
The orca had been involved in two previous deaths, including one at the water park in 1999.
Dawn Brancheau, 40, was finishing a session with Tilikum, a 12,000-pound male killer whale, after a midday show at the Orlando theme park, The Los Angeles Times reports.
According to Orlando Sentinel, SeaWorld trainers were forbidden from swimming with Tilikum, as they often did with the resort's seven other orcas.
Only about a dozen of 28 handlers, including Brancheau, had been specifically trained to work with him from the edge of SeaWorld's pools.
There were conflicting reports about the incident, with authorities saying the woman had died after apparently falling into the whale's tank and an eyewitness claiming the animal leapt out of the water to grab her in its mouth.
"One of our most experienced animal trainers drowned in an incident with one of our killer whales this afternoon," said Dan Brown, general manager at the Orlando entertainment park.
"This is an extraordinarily difficult time for the SeaWorld parks," he added at a televised press conference.
Jim Solomons, from the Orange County Sheriff's office, said the trainer, who was not named, died after falling into the tank by accident, National Post reports.