Tilikum drowned his trainer in front of a live audience in 2010. It was not the first time he had killed a human. Two earlier deaths had already been linked to the same orca while in captivity.

Tilikum, the 12,000-pound bull orca whose big splashes still climax daily SeaWorld shows, has been implicated in three human deaths, spread over his three decades of forced performances: Two trainers, ...