A trainer at the SeaWorld park in Orlando, Florida, has died after being attacked by a killer whale after she innocently swung her ponytail which attracted his attention.

What we have found out is that Dawn [Brancheau] had just finished up a very good session with this animal... She was interacting with him, petting him on the nose, Chuck Tompkins, curator of zoological operations at SeaWorld Orlando, told Good Morning America.

 Dawn had very long hair in a ponytail. That ponytail had swung in front of him. He grabbed her by the hair and pulled her underwater and held her underwater.

This was not the first time the killer whale called Tillikum. According to BBC, 12,000 pound killer whale was also involved in the death of a female trainer in Canada in 1991.

The 40-year-old woman, Brancheau, was thrashed viciously underwater.

Within minutes the Shamu Stadium, where the killer whale show takes place, was evacuated.

Brancheau was pronounced dead at the scene, Orange County Sheriff's homicide investigators said Wednesday.