Psychoactive drugs similar to Valium have been injected into whales at Sea World to control their aggressive behavior, documents have revealed.

In a bitter court case between the marine park and its rival Marineland, it has been revealed that orcas, or killer whales, are given doses of benzodiazepine, UK MailOnline reported.

Used to simmer down anxiety levels and cause drowsiness, the valium and xanax containing drug's prolonged use cane bring out panic attacks, out-of-body experiences, and muscle spasms.

In 2013, the treatment of whales at the marine park in Florida was documented in an eye-opening documentary. This had caused huge uproar and a widespread year-long boycott.

The latest scandal has been branded as the "final straw" by animal right activists, UK MailOnline reported.

"The end is near" for SeaWorld, PETA told MailOnline.

"SeaWorld is in deep trouble and hot water since Blackfish showed the mental anguish of orcas taken from the great oceans and trapped for eternity in SeaWorld's swimming pools - and now court documents have revealed that SeaWorld also pumps these marine slaves full of psychotropic drugs in order to force them to perform stupid tricks," the animal rights organization said in a statement.

"If SeaWorld executives were locked up within our prison system, they would experience luxurious accommodation in comparison to those of the highly social, intelligent marine animals they imprison, which cause them to lash out, chew their own teeth to the nubs and attack their trainers."

"SeaWorld can dress the issue up however it likes, but when investors want out, it's a sign that the end is near," the statement said.

Lanny Cornell, former SeaWorld vice president, confirmed the allegations in a statement to the court.

However, the medication of Benzodiazepine was defended by a spokesperson for SeaWorld.

"Benzodiazepines are sometimes used in veterinary medicine for the care and treatment of animals, both domestic and in a zoological setting," he said in a statement. "These medications can be used for sedation for medical procedures, premedication prior to general anesthesia, and for the control of seizures."

"The use of benzodiazepines is regulated, and these medications are only prescribed to animals by a veterinarian. Their use for cetacean healthcare, including killer whales, is limited, infrequent, and only as clinically indicated based on the assessment of the attending veterinarian. There is no higher priority for SeaWorld than the health and well-being of the animals in its care."