Expressen TV sent a young reporter out onto the streets of Sochi with a "wanted" poster sporting a photograph of the Norwegian star, whose rivalry with Swedish skiers Marcus Hellner and Calle Halfvarsson is legendary.
"Have you seen the man? We were just wondering, this guy here in the picture," she asked a succession of bemused locals. "No? Me neither. But everybody here in Sweden is looking for him, and we don't know where he is."
The TV channel popped the same question to Mads Gudim Burheim, a reporter with Norway's Dagbladet newspaper, and then launched a gallery entitled, "Can you help Northug across the finishing line?", which encouraged users to click on a series of 38 pictures of the star at various stages in the race in the hope that they could cheer him on.
Northug was beaten by four Swedes in the race, with his arch rival Marcus Hellner taking silver behind Switzerland's Dario Cologna with gold.
His fellow Norwegian, Martin Johnsrud Sundby, took bronze, but the medal was contested on Sunday by the Russian team, which claims that Sundby crossed into his rival's lane a few metres before the finish. The International Ski Federation has 72 hours to make a ruling.
The Norwegian faced mocking questions from Swedish journalists almost as soon as he crossed the finishing line.
"How does it feel to be beaten by four Swedes?," one journalist asked him.
Northug is famed for his overt competitiveness and in December threatened to "destroy the life" of his Russian counterpart Maxim Vylegzhanin when the two teams meet at Sochi.
On Sunday, he was more subdued, saying that he had decided to slow up once he realized he could not win a medal.
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"I suppose I could have gone quite a bit faster up the last hill and got to a better location, but when you can not win a medal, then you have to think about the next race," he said.
While Northug has faced fitness problems since the middle of last year, his Swedish rival appeared to be in good form he said.
"Marcus seems to be in solid shape, so he is hard to deal with here," he said.