In 1991, a trainer at Sealand in Victori slipped into a pool with the 12,000 pound Orca named Tilikum and two other whales. She was batted around by the whales until she drowned.

After the incident, animal rights activists argued the whales should be set free and not sold to Sea World where they might hurt someone else.

Then in 1999 at the Orlando SeaWorld, the body of a naked man was found scratched, bruised and draped over the back of Tilikum.

Daniel Dukes, 27, 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 that he died of hypothermia in the 50-degree water. Dukes' parents filed a lawsuit against the park later that year but later withdrew it.

WATCH IT: Whale Kills Trainer SLIDESHOW: Aerials Of SeaWorld Orlando Photos courtesy WFTV.com

In Wednesday's attack, that same whale attacked the 40-year-old trainer, identified as Dawn Brancheau.

According to WFTV, Brancheau was rubbing Tilikum from a poolside platform when the whale reached up, grabbed her with its mouth and dragged her underwater. Despite workers rushing to help, the trainer was killed.

"She was standing on the rocks right above the viewing area. He jumped, took off, came back, grabbed her and started thrashing her around. Her shoe fell off. He was thrashing her pretty good, it was violent," said Victoria Biniak who witnessed the attack.

Orange County Fire Rescue spokesman John Mulhall said paramedics who were called to the Shamu Stadium at the theme park resort found the woman, who could not be revived. It was not clear if she drowned or died from the thrashing.

WFTV.com Whale attack victim, Dawn Brancheau 40-year-old SeaWorld trainer Dawn Brancheau was killed at SeaWorld Orlando.

A guest who saw the whale show less than an hour before the fatal attack talked by phone from the park to WFTV about the whales' strange behavior.

“All of the sudden, out of nowhere, two of the bigger whales just kind of flipped out, going as fast as they could in the water,” guest David Dalton told Eyewitness News. “They cut off the show, like, quickly.”

Half of the Orlando park was closed down Wednesday afternoon as a result of the incident and a spokesman said SeaWorld suspended the killer whale show in San Diego.

Seattle Orca expert Fred Felleman said the whales are very social animals and keeping them in isolation is bound to make one of them snap at some point.

WATCH IT: Death Raises Questions About Orcas In Captivity

“There should be an outcry. The fact is we don't have the facilities to accommodate the physical needs, but also the social needs of these animals." Felleman said.

He said the aquariums mischaracterized killer whales as animals that people would want to swim with.

“We respect lions and wolves and wild dogs. We don't go run into the Serengeti and try to go jump on their backs," Felleman said. “You bring out the worst in an animal if you go against 30 million years of evolution, and say, 'Oh, no you need to serve our needs now.’"

There have been several previous attacks on whale trainers at SeaWorld parks.

In Nov. 2006, trainer Kenneth Peters, 39, was bitten and held underwater several times by a 7,000-pound killer whale during a show at SeaWorld's San Diego park. He escaped with a broken foot.

The 17-foot-long orca who attacked him was the dominant female of SeaWorld San Diego's seven killer whales. She had attacked Peters two other times, in 1993 and 1999.

In 2004, another whale at the company's San Antonio park tried to hit one of the trainers and attempted to bite him. He also escaped.

In December, a whale drowned a trainer at a Spanish zoo.

Tilikum is the largest killer whale in captivity.