March 30 (UPI) — The Supreme Court on Monday denied an appeal from Joe Exotic, the former Tiger King star who is serving time for trying to have an animal rights activist killed.

The court declined to consider tossing the 2019 conviction of Joe Exotic for a murder-for-hire plot to kill animal rights activist Carole Baskin. Joe Exotic, whose real name is Joseph Maldonado-Passage, is serving 21 years for the plot. He was also convicted of falsifying wildlife records and violating the Endangered Species Act.

Baskin was also part of the Tiger King series. She founded Florida rescue center Big Cat Rescue and was an advocate of the Big Cat Public Safety Act, which limited owning big cats and cross-breeds to wildlife sanctuaries, state universities and certified zoos. Former President Joe Biden signed the law in 2022.

Maldonado-Passage’s lawyer, Alexander Roots, told the court that the case arose out of an “intense personal, litigation, operational, and even political, rivalry between two of America’s two largest big cat exhibitors,” The Hill reported.

“By denying any hearing and by refusing to evaluate the evidence as a whole, the lower courts departed from principles that safeguard every criminal prosecution in the nation,” he wrote in the petition to the court.

At the trial in 2019, prosecutors said Maldonado-Passage, 63, hired two men to kill Baskin, one of whom was an FBI agent. They also said he shot and killed five tigers in October 2017 and sold and offered to sell tiger cubs.

Maldonado-Passage has asked President Donald Trump for a pardon. He also asked Biden while he was in office.

In his feud with Baskin, Maldonado-Passage alleged without evidence that she killed her second husband, who disappeared in 1997, and he rebranded his traveling show Big Cat Rescue Entertainment, for which she sued him for trademark infringement. He settled with her for $1 million.

In his petition to the Supreme Court, Maldonado-Passage argued that the lower courts “shrugged off” evidence that three witnesses had recanted their trial testimony, including Allen Glover, a zoo employee and the other hired hitman, and Florida businessman James Garretson.

He also alleged federal prosecutors failed to tell the defense that the witnesses were promised immunity for testifying.

But the 10th U.S. Circuit Court of Appeals said the new evidence wasn’t likely to change the trial’s result.

In July, Bhagavan “Doc” Antle, 65, another Tiger King alum, was sentenced to federal prison for crimes related to trafficking exotic animals. He was given 12 months and one day, plus a $55,000 fine and three years of supervised release for violating the Lacey Act, which bans the sale of illegally acquired wildlife, fish or plants, including those designated as protected species by the federal government.