Dawn Brancheau, 40, a trainer at SeaWorld for 16 years, had just fed fish from the poolside to the large male, called Tilikum, having finished a show with him.
Stepping on to a shallow-water ledge at the pool's edge, Brancheau then lay down to interact face-to-face with the orca, or killer, whale which she knew well.
Witnesses described how Tilikum, reportedly the largest orca in captivity with a history of violence, lunged at Brancheau. It managed to grab her ponytail and hauled her off the ledge into the deep pool water.
The whale then took hold of Brancheau by the waist and both thrashed her about and held her under water until she was dead.
Seaworld’s head of animal training, Chuck Tompkins, confirmed that Brancheau had been “rubbing the killer whale’s head” when it “grabbed her and pulled her in”.
"Dawn had just finished up a very good session with this animal. She was petting him on the nose,” he said. "Dawn's long ponytail swung in front of him. He grabbed her by the hair and pulled her under."
Eyewitnesses were reportedly shocked by the violence with which Brancheau was shaken and dragged down. A published autopsy has confirmed that she had “most likely died from multiple traumatic injuries and drowning”.
Tilikum, a long-term captive whale, has been implicated in the deaths of two other people over the past 19 years.
In 1991, at a marine park in Canada, he and two female orcas were blamed for the death of a trainer, 20-year-old Keltie Byrne, after she slipped into the water with them.
In 1999, after Tilikum had been purchased by SeaWorld, homeless Daniel Dukes was found dead in the whale’s pool after gaining unauthorised access after hours and going swimming with him.
Conservation groups have commented on the incident as an example of dangers posed by placing wild animals in captivity and trying to manipulate them.
The World Society for the Protection of Animals, for instance, has said that Brancheau's death is "a sad reminder of the inappropriateness of keeping these animals in captivity".
And according to the Whale and Dolphin Conservation Society, "the tragic events are a reminder that orcas are wild, strong and often unpredictable animals".
The creatures, it says, are "unsuitable for captivity" and "are liable to aggressive behaviour towards humans and other orcas that is never seen in the wild".
Tompkins has responded: "You're going to have all these activists coming out of the woodwork to try to take advantage of a very sad situation. To say these animals have the wrong environment is so incorrect.”
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