Tilikum, the killer whale featured in the documentary "Blackfish" that made the case against keeping orcas in captivity died on Jan. 6. (Reuters)

Tilikum, the most famous killer whale in the United States, died Friday after a year-long illness and quarter century of performances streaked with violence.

The many-tonned orca — believed to be 36 years old and linked to the deaths of three people in that time — likely succumbed to a lung infection early in the morning, according to a statement released by SeaWorld.

The whale died at the Orlando marine park where he spent most of his life, “surrounded by the trainers, care staff and veterinarians that provided him around-the-clock world-class care,” the statement reads.

Tilikum had been sick since last spring, when a SeaWorld veterinarian, voice cracking, warned that the whale’s bacterial infection was “chronic and progressive.”

SeaWorld eulogized a “long and enriching life” that “inspired millions of people.” Others noted a dark current in the whale’s biography.

“From the moment he was taken from his ocean family, his life was tragic and filled with pain,” reads a statement from PETA, one of many groups that Tilikum inspired to fight against whale captivity.

Tilikum “has shouldered a fraught history, emerging as the symbol of both orcas’ elegance and their capacity for violence,” The Washington Post’s Yanan Wang wrote in a profile of the whale last March.

Born wild in the icy waters of west Iceland, Wang wrote, he was first netted in 1983 — in an era when killer whales were coveted by marine parks and adored by crowds.

Tilikum was taken from the ocean to a concrete tank, Wang wrote, held there for a year before being shipped to British Columbia to perform at Sealand of the Pacific.

A trainer told CNN that Tilikum was the easiest to work with in Sealand’s stable. He was virile, too, siring many calves before 1991, when a part-time trainer slipped into the orca tank.

A whale grabbed 20-year-old Keltie Byrne’s foot and pulled her underwater, Wang wrote. The whales thrashed her around the tank. She screamed until she drowned.

Sealand never recovered. “They closed in 1992, a year after selling their killer whales to SeaWorld,” which reportedly wanted Tilikum for breeding at its state-of-the-art theme park, Wang wrote.

Tilikum spent seven years in Orlando before another body turned up in his tank.

In 1999, 27-year-old Daniel Dukes was released from a county jail and apparently snuck into the park at night. He was found drowned and draped across Tilikum’s back, Wang reported.

Still, the whale drew crowds, even after February 2010, when SeaWorld’s star trainer and spokesmodel Dawn Brancheau leaned over Tilikum’s tank and was grabbed in his jaws by her hair.

She was thrashed in the water, like Byrnes before her. Like the others, she died.

Yet the show went on. Tilikum returned to public performances after a year-long hiatus, Wang reported.

His public image did not begin to change — and SeaWorld’s with it — until the documentary “Blackfish” was released in 2013.

Largely centered around Tilikum and his body count, the film portrayed the whale as a victim of captivity — made “psychotic,” as one researcher put it.

SeaWorld called the movie propaganda. But within a year, a backlash against the park had caused SeaWorld’s attendance to fall and its stock prices to dive.

Southwest Airlines ended a 26-year-old partnership with the marine park. The company’s chief executive resigned. Animal rights groups called for Tilikum’s freedom, while lawmakers talked of banning captive whale breeding.

In 2014, SeaWorld announced that it would the stop the practice voluntarily.

“Society is changing,” the organization said. Tilikum’s “will be the last generation of orcas at SeaWorld.”

The whale had not performed since his illness was announced last year, though the park posted regular reports on his health for his fans.

“Tilikum has some good days and some not so good days,” reads an update from June.

Tilikum died much older than most captive orcas, SeaWorld said Friday. The Post has noted that wild whales live much longer.

He sired at least 21 calves before his death, 14 of them at SeaWorld.

The company still owns 28 orcas, among its parks in Orlando, San Antonio, Spain and San Diego. The San Diego park will hold its last killer whale show this weekend.

More reading:

Tilikum, the SeaWorld killer whale at the center of ‘Blackfish,’ is slowly dying

Three whales have died at SeaWorld San Antonio in the last six months

Beleaguered SeaWorld admits employees spied on animal rights activists