Dawn Brancheau, an experienced trainer who understood the dangers of her job, was killed by a killer whale at the SeaWorld Shamu Stadium in Orlando, Fla., on Wednesday. (Julie Fletcher/Orlando Sentinel/Associated Press)

A killer whale who killed a trainer in front of a live audience at SeaWorld Orlando on Wednesday has been involved in two other deaths, including one in Victoria, B.C., almost 20 years ago.

Officials say the whale, called Tilikum, grabbed Dawn Brancheau, 40, in its jaw and thrashed her around underwater as the horrified Florida crowd looked on. It's not clear if Brancheau, an experienced trainer, drowned or died from the physical attack.

An aerial view of the SeaWorld theme park in Orlando. (Reuters)

Spectator Victoria Biniak told WKMG-TV that the veteran trainer had just finished explaining to audience members a show they were about to see when the whale grabbed her. Police said Brancheau slipped, or fell, into the tank, but several witnesses said the animal leaped out of the water and dragged her in.

A former SeaWorld contractor told the Orlando Sentinel that Tilikum is typically kept isolated from other whales because of the animal's history of danger. Trainers are also not allowed to get into the tank with it.

SeaWorld spokesman Fred Jacobs said that in 1991, Tilikum was one of three whales involved in the death of trainer Keltie Byrne, who had fallen into the pool at Sealand in Victoria and was dragged under water by the whales.

In 1999, after Tilikum was moved to Orlando SeaWorld because he was considered a threat to a calf, the body of a naked man was found scratched, bruised and draped over the whale.

The man, 27-year-old Daniel Dukes, had reportedly made his way past security at SeaWorld, remaining in the park after it had closed. Wearing only his underwear, Dukes either jumped, fell or was pulled into the frigid water of Tilikum's huge tank.

An autopsy ruled Dukes died of hypothermia, but it also appeared Tilikum bit the man and tore off his swimming trunks, likely believing he was a toy.

Brancheau drawn to career at age 9

According to a profile of Brancheau in the Sentinel published in 2006, she was drawn to her career after she visited SeaWorld when she was just 9.

"I remember walking down the aisle [of the stadium] and telling my mom, 'This is what I want to do,"' she said in the article.

Brancheau, who worked as a trainer for 12 years, knew the dangers of the job.

"You can't put yourself in the water unless you trust them and they trust you," she said.

Steve McCulloch, founder and program manager at the marine mammal research and conservation program at Florida Atlantic University's Harbor Branch, said the whale may have been playing when it attacked Brancheau, but it is too early to tell.

"I wouldn't jump to conclusions," he said. "These are very large, powerful marine mammals. They exhibit this type of behaviour in the wild.

"Nobody cares more about the animal than the trainer. It's just hard to fathom that this has happened."

With files from The Associated Press