A female trainer was killed today at SeaWorld's Shamu Stadium in Orlando, Fla., by a 12,000-pound killer whale that had twice before been involved in the deaths of humans, according to police and local media.
There is still confusion about how a killer whale killed a SeaWorld trainer.
Dawn Brancheau, 40, an experienced trainer at the tourist attraction, was pulled into the tank by the killer whale, Chuck Tompkins, head of animal training at all SeaWorld parks, said this evening.
Tompkins told ABC News Orlando affiliate WFTV that Brancheau was rubbing down the whale after an afternoon show, when the incident occurred.
"She was pulled in and she drowned," he said.
Earlier, police had said Brancheau slipped or fell into a tank holding the killer whale, Tillikum, and witnesses described the animal coming to the surface to attack the woman.
"Brancheau was pronounced dead at the park after being recovered from the pool. Orange County Sheriff's Office homicide investigators continue to investigate the death of the trainer who was reported to have 16 years of experience working with killer whales," the Orange County Sheriff's Office said in an e-mailed release.
Tillikum, a male or bull whale, has lived at the park since 1992, and is one of eight killer whales there.
"Currently, deputies with the full cooperation of SeaWorld have secured the scene and homicide detectives have been requested to respond and conduct a death investigation follow-up, along with our forensics unit," said Capt. Angelo Nieves of the Orange County Sheriff's Office in a statement.
One witness, park visitor Victoria Biniak, told WKMG-TV that she watched the whale grab Brancheau.
"He was thrashing her around pretty good. It was violent," Biniak said.
The whale "took off really fast in the tank, and then he came back, shot up in the air, grabbed the trainer by the waist and started thrashing around, and one of her shoes flew off," she said.
Visitors were evacuated and the park closed following the attack.
A trainer and a whale similar to the whale involved in the incident during a SeaWorld show on February 17, 2010. 

Dawn Brancheau, a whale trainer, died in an accident at the SeaWorld in Orlando, Florida on Wednesday, at around 14:00 local time. The incident involved an 18-year-old killer whale, Tillikum, also called Tilly. The Orange County Sheriff's Office report that trainer Brancheau has 16 years of experience. Brancheau was reported dead after being recovered from the pool.

Witness to the incident Victoria Biniak told WKMG-TV, "He was thrashing her around pretty good. It was violent. The whale ...took off really fast in the tank, and then he came back, shot up in the air, grabbed the trainer by the waist and started thrashing around, and one of her shoes flew off." 

In response to this accident, SeaWorld San Diego canceled its Shamu show, a show involving the whales at the San Diego location. "We're terribly saddened by the loss of the member of our SeaWorld family, it doesn't matter what park," David Koontz, a spokesperson for SeaWorld San Diego said.