Hvaldimir, a whale believed to have escaped a past life as a Russian spy, was found dead over the weekend in what animal rights organizations say were unnatural circumstances.

The beluga whale became internationally popular after he was discovered by fishermen off the coast of Norway in 2019 wearing a camera harness that read “Equipment St. Petersburg.” Theories about his past sparked interest around the world, and his friendly demeanor won him tons of admirers over the years. Hvaldimir frequented the Norwegian coast, visiting fish farms and actively seeking out human interaction. He was huge, measuring 13 feet long and weighing about 2,000 pounds. He was popular on social media, going viral for retrieving a kayaker’s dropped GoPro camera, playing fetch with a rugby ball and playing with an underwater drone.

OneWhale, a nonprofit founded in 2019, advocated for Hvaldimir’s protection from “tourism and other dangers” and was actively working to relocate Hvaldimir to a wild beluga population in the Arctic, where belugas are normally found. The organization had recently announced plans to transport him in the fall, but early in September he was discovered floating dead or dying. Scientists who viewed him do not believe his death was a natural one and his body has been sent for a necropsy — an autopsy for animals.