PETA is demanding that the City of Toronto’s Animal Services' Enforcement and Mobile Response unit investigate what it says was the “unlawful exhibition” of a tiger and other exotic animals at an engagement party for Justin Bieber's father.

Bieber posted photos to Instagram showing himself petting a tiger at the party, which was held over the weekend at a private residence in the city.

PETA said in a statement Thursday that the tiger’s markings are distinctive and it believes the tiger was brought in from the Bowmanville Zoo.

A spokesperson for the zoo told CP24 on Monday that it could not confirm nor deny that its tiger had been at the party, saying it was not a zoo event.

The Bowmanville Zoo's owner, Michael Hackenberger, is currently facing five charges of animal cruelty, after a video surfaced of a tiger being repeatedly whipped by a trainer.

PETA says that, under Toronto’s own bylaws, the possession of exotic animals in the city is prohibited, and that violations are supposed to be punishable by a fine of up to $5,000. It has filed a formal complaint with the city, calling for an investigation.

"With a powerful adult tiger restrained only by a leash and a lion or tiger cub torn away from his or her mother's side, this dangerous and inhumane party seems to have also been against the law," PETA Foundation Deputy Director of Captive Animal Law Enforcement, Brittany Peet, said in a statement.

"PETA is calling for an investigation into who was paid to parade wild animals at this event, and we urge kind people everywhere not to participate in disgusting exotic-animal photo ops like this one."

After Bieber posted the photo, PETA called on him to pledge that he would no longer use exotic animals for photos or selfies. Bieber has not responded.

Bieber came under PETA's scrutiny in 2013, when his pet capuchin monkey, Mally, was confiscated at an airport in Germany because he didn’t have proper documentation for the animal. The monkey was later placed in a zoo along with other monkeys.