From what people are describing this death seems very similar to that of Keltie Byrne, the trainer at SeaLand Pacific who fell in and the whales proceeded to "Play" with her body, tossing it from one to another for a prolonged period of time and pushing her to the bottom of the tank until she died from drowning.
Daniel Dukes was incredibly stupid and was found to have died from hypothermia and drowning but he was found with marks all over his body concordant with being dragged across the bottom of the tank by Tilikum.
In my first post I wasn't suggesting for e.g that Tilikum should be destroyed but neither do I think he should have been made to perform or used as entertainment. He doesn't know what he is capable of and doesn't understand that humans can't hold their breath. I really don't think he should have been kept in captivity. And this will happen again as long as killer whales continue to perform in unnatural environments. Instead of breeding them in captivity the orcas captured from the wild should have been allowed to die out naturally if they couldn't be released without being used to populate theme parks. They are beautiful and intelligent but they were not made to be our best-friends or celebrities.