– Tilikum, the SeaWorld killer whale that inspired the anti-captivity documentary "Blackfish" after killing a trainer, has died.

SeaWorld said Tilikum had been battling a serious and persistent lung infection.

Acquired by SeaWorld in 1992, Tilikum helped SeaWorld grow its captive orca collection by fathering more than a dozen offspring. But Tilikum also triggered a downward spiral for SeaWorld after the massive orca killed trainer Dawn Brancheau in 2010.

That triggered a torrent of controversy and led to the documentary "Blackfish." The 2013 movie took an in-depth look at Tilikum's life and argued that the stress of captivity turned him into a killer. Three years after the film's release, SeaWorld is still dealing with the financial and public relations effects from it.

SeaWorld said in a statement that Tilikum had received great care. It also acknowledged its difficult past.

"Tilikum's life will always be inextricably connected with the loss of our dear friend and colleague, Dawn Brancheau," SeaWorld said in a statement. "While we all experienced profound sadness about that loss, we continued to offer Tilikum the best care possible, each and every day."

Tilikum was captured from the waters near Iceland as a youngster and sent to the now-defunct Sealand of the Pacific in Victoria, British Columbia. There, "Blackfish" and "Death at SeaWorld" chronicle that dominant females attacked him and he was locked in an underwater cage every night.

In 1991, Tilikum and two other orcas drowned trainer Keltie Byrne. Sealand put the three whales up for sale about seven months later. SeaWorld Orlando had asked to receive Tilikum because the park said its staff could provide veterinary care the whale would not be able to receive in Canada.

PBS' "Frontline" said the females were pregnant and had begun being aggressive to Tilikum. They put him in a small medical holding tank.

In 1999, the naked body of Daniel Dukes, who had apparently sneaked into SeaWorld after hours for a swim, was found dead on Tilikum's back.

Authorities later concluded Dukes likely suffered hypothermia and drowned, but they said it also appeared Tilikum bit the man's body and tore off his trunks after he had died.

After Brancheau's death, SeaWorld put changes into effect that included requiring trainers to stay farther away from Tilikum when working with him. Tilikum went back to performing the year after Brancheau's death, and he was appearing in shows up until nearly the time that he died.