According to the first reports about the attack on Dawn Brancheau, trainer, by a killer whale, Brancheau fell into the water, the whale rose to the surface, grabbed her and took her under water, drowning her. A witness describing the event not long after it happened gave a different scenario: the whale (Tillikum), was obviously agitated before the attack, and it was definitely an attack; the whale thrashed her back and forth before taking her under. Then other details emerge: Brancheau was feeding the animals, threw a bucket of water (perhaps with fish in it) on a whale. Tillikum had been involved in the deaths of two other humans. In one of those cases, two killer whales had participated with him.
A most important question this horrible event raises is why was Tillikum still performing before the public, especially anywhere near a trainer or any human being? His actions are probably absolutely natural to his kind in that situation: Killer whales hunt and kill seals in the same manner as this attack; sometimes males join together in hunting packs. He’s a predator and has been acting like one. Brancheau’s death seems totally avoidable and therefore even more tragic.