The death of a beloved white beluga whale has turned into a mystery in Norway as animal rights groups speculate whether he was actually assassinated.

The beluga, nicknamed Hvaldimir, rose to fame in 2019 after being spotted wearing a specially-made harness with mounts for a camera, sparking claims that the animal may have been trained by the Russian military.

Two Norwegian animal rights groups alleged on Wednesday that the whale was “shot to death” after Hvaldimir was found dead over the weekend in southern Norway.

OneWhale and NOAH are calling for a criminal investigation “based on compelling evidence that the whale was killed by gunshot wounds,” OneWhale, which describes itself as a “nonprofit committed to protecting Hvaldimir and relocating him to a wild population of belugas,” wrote in an Instagram post.

It added that “several veterinarians, biologists, and ballistics experts have reviewed [the] evidence of Hvaldimir’s injuries, determining that the whale’s death was the result of a criminal act.”

The organizations filed a police report to the Sandnes Police District and the Norwegian National Authority for Investigation and Prosecution of Economic and Environmental Crime.

“I don’t think we’ve had a case like this before,” said Southwestern Police District Superintendent Victor Fenne-jensen, who declined to comment on whether his department had investigated rumors that the whale was a Russian spy.

He added, Hvaldimir was “kind of a celebrity.”

However, Marine Mind, another non-profit that advocates for protecting marine life, has called the public to “refrain from speculation” until the country’s Veterinary Institute has finished its own investigation.

It was Marine Mind that found Hvaldimir’s body in the bay. “When we found Hvaldimir on Saturday, it was not possible to immediately determine the cause of death, and therefore it is important to refrain from speculation until the institute has completed its work,” Marine Mind posted to its Facebook page on Wednesday.

Norwegian public broadcaster NRK reported that his body was found floating at the Risavika Bay in southern Norway Saturday by a father and son who were fishing, according to the Associated Press (AP).

The beluga, named by combining the Norwegian word for whale — hval — and the first name of Russian President Vladimir Putin, was lifted out of the water with a crane and taken to a nearby harbor where experts for experts to examine, AP reported.

Marine biologist Sebastian Strand told NRK Hvaldimir’s cause of death was not immediately clear and that no major external injuries were visible on the animal, the AP reported.

That the harness clips read “Equipment St. Petersburg” only contributed to the popular theory that he came from Murmansk, Russia, and was trained by the Russian navy.