A harness-wearing beluga whale known for sparking speculation that he was a spy trained by the Russian navy has died, marine organizations tracking him said Saturday. 

Hvaldimir, spotted with the harness in 2019, was found dead in heavily trafficked waters just outside of Stavanger, Norway, according to OneWhale.The organization does not believe the beluga’s death was natural and has asked Norwegian authorities to perform a necropsy. 

“We are heartbroken,” OneWhale wrote in a Facebook post. “We are angry, too, as we have had to fight so hard, for so long to help him out of danger. And he was finally so close to having a better life. But We are angry at those who worked to block his move and spread misinformation.” 

Hvaldimir may have been killed by a ship strike, a OneWhale member said. Before his death, the beluga was healthy, fit and a good weight. He also did not show any signs of having any diseases. 

Belugas are vulnerable to pollution, habitat degradation, harassment, interactions with commercial and recreational fisheries, oil and gas exploration, disease, predation from killer whales and other types of human disturbance, according to the National Oceanic and Atmospheric Administration. The population was also once threatened by commercial and sport hunting. 

Hvaldimir was given his name based on “Hval,” the Norwegian word for whale and “Vladimir, ” a nod to Russian President Vladimir Putin and the whale’s alleged association with Russia. 

The Russian military has a history of trying to weaponize sea mammals, CBS News previously reported. Last year, British military spies said Russia appeared to be training combat dolphins to counter Ukrainian forces. 

Hvaldimir was comfortable with people and would retrieve rings thrown into the water, according to previous reports. A OneWhale member described him as a “sweet, loving, kind and gentle angel of a whale.”