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.