whaleWow, it turns out that the SeaWorld whale which just killed a trainer has killed before.

Here's the WIkipedia entry for Tilikum:

Tillikum was first sent to live at Sealand of the Pacific near Victoria, British Columbia. There, he lived with two older females named Haida II and Nootka IV. While living in British Columbia, Tilikum sired his first calf when he was about eight or nine years old. His first son, Kyuquot, was born to Haida II on December 24, 1991. Just a few months prior to the birth of Kyuquot, Tilikum was involved in an incident which resulted in the death of a trainer. Twenty-year-old Keltie Byrne, who worked at the park, slipped and fell into the tank with the whales. Tillikum, a pregnant Haida II, and Nootka IV grabbed her in their mouths and tossed her to each other, presumably playing. Keltie drowned. The orcas had never had humans in the water with them before. Haida II and Nootka IV were overprotective of the newborn calf and aggressive towards Tillikum, who was forced into the small medical pool. Because of his huge size, Seaworld requested an emergency transfer to their facility. Tilikum was moved to SeaWorld Orlando, Florida in January 9, 1992; he has been there ever since. Sealand of the Pacific closed soon thereafter.

Since his arrival at SeaWorld, Tilikum has sired many calves with many different females. His first calf, born in Orlando, was to Katina. Katina gave birth to Taku on September 9, 1993. Tillikum's other calves are: Nyar (born 1993, died 1996), Unna (1996), Sumar (1998), Tuar (1999), Tekoa (2000), Nakai (2001), Kohana (2002), Ikaika (2002), Skyla (2004), and Malia (2007). In 1999, Tillikum began training for artificial insemination (AI). In early 2000, Kasatka who resides at SeaWorld San Diego was artificially inseminated using his sperm. She gave birth to Tillikum's son, Nakai, on September 1, 2001. On May 3, 2002, another female in San Diego, named Takara, bore Tilikum's calf through AI.

Tilikum was at the scene of another death on July 6, 1999, though evidence suggests the Orca was not at fault. A park guest, 27-year-old Daniel Dukes, was found floating naked in Tilikum’s pool, apparently killed by a combination of hypothermia and drowning. Dukes had visited SeaWorld the previous day, stayed after the park closed, and evaded security to enter the Orca tank.

Tilikum never takes part in water work with trainers, not necessarily due to aggression (he is in fact very docile), but because he doesn't necessarily realize his own strength. Tilikum is the feature of the show "Believe" where the audience and trainers chant "Shamu" as Tillikum soaks the audience.[34] On February 24th, 2010 Tilikum was involved in a fatal accident with a female trainer. Witnesses report that during a show the whale grabbed a trainer by the waist and started thrashing her around. The attack was so violent the trainer's shoes were thrown off. The incident is currently under investigation. [35]