When Morten Vikeby saw reports that a “spy whale” from Russia had been found off the Norwegian coast, he immediately phoned his old fishery newspaper Fiskeribladet with a tip, wrote theguardian.com.

The amiable beluga reminded him not of a spy, he said, but of a “therapy whale” he’d seen a decade ago at a diving centre in northern Russia.

That whale, named Semyon, lived in a watery enclosure in Russia’s Murmansk region, and sometimes entertained tour groups of children with mental disabilities.

“Maybe it wasn’t the same whale but it acted the same way,” said Vikeby, a former Norwegian consul to the city of Murmansk, in a telephone interview. “The whale has been accused of espionage. I see it as my big purpose to defend him.”

The tame beluga found off Norway’s Ingoya island has become a local celebrity. Locals have christened him “Hvaldimir”, a portmanteau of the Norwegian word for whale, hval, and the popular Russian name, Vladimir.

A regular in the sea by the harbour city of Hammerfest, he even retrieved a woman’s iPhone after she dropped it in the water earlier this week.

But the harness he was wearing when he was found, bearing a buckle stamped “Equipment St Petersburg”, has dogged his reputation, fuelling speculation that he escaped a military training programme in Russia’s north.

After all, who else would have put a harness on a whale, perhaps to hold a camera, and then not publicly admit it had gone missing?

Dmitry Glazov, a Russian scientist and deputy head of the beluga white whale programme, said that near Murmansk alone there were “three organisations, not necessarily military, some civilian, that train marine mammals, including belugas, for various tasks: retrieving objects, or finding divers who have had problems, like equipment malfunctions”.

But he said the presence of a harness alone would not confirm that Hvaldimir has any ties to the Russian military.

“These kinds of buckles are sold all across Russia,” he said.

The likelihood that Hvaldimir is the same whale that Vikeby saw in Russia in 2008 is a long shot.

“For the last two and a half years, there haven’t been any whales here,” said Mikhail Safonov, the head of the Arctic Circle dive centre. The whales belonged to a separate organisation called the Belomorsk Ecological Centre, Safonov said, adding that he believed they had sold the last whale to the St Petersburg Oceanarium in 2016.

A representative for that company and the St Petersburg Oceanarium could not immediately be reached on Thursday, a national holiday in Russia.

Safonov said he never saw those belugas wear harnesses and they “never had tasks or exercises where they would exit the enclosure into the sea”.

By the beluga’s appearance, Hvaldimir appeared to have been caught in the far east, Glazov said, from where whales are sold on to oceanariums, where they are trained for public performances, and research institutes throughout Russia.

But the industry has been rocked this year by a national scandal over a so-called “whale jail” in Russia’s far east, where 11 orcas and 87 belugas were held captive in appalling conditions before being sold. Some newspapers called it a “concentration camp” for whales. The Russian president, Vladimir Putin, personally intervened in the situation.

Since then, admitting the loss of a whale would be more likely to attract unwanted attention from the media and officials.

“It’s a bad time to lose a whale,” said one Russian researcher, who asked not to be identified in order to speak candidly.

Glazov said that there could be a number of reasons not to go public about the lost whale.

“They may be scared of their bosses,” he said. “They may fear public attention. And they may be scared to make public what they were doing, if it’s a closed organisation with ties to the military.”