The mysterious bones were found on Kråkholmen near the island of Tjörn, around 50 kilometres north-west of the city of Gothenburg at around noon on Tuesday.
Police revealed on Wednesday that a forensic investigation had confirmed that the bones – which were initially thought to possibly belong to an animal – were human remains dating back to the 1940s.
“They probably are from the time around the war. They're probably so old that they come from the period around the Second World War,” police press spokesman Stefan Gustafsson told regional newspaper GP.
He added that other items found at the scene supported suspicions the bones belonged to a soldier who died during the Second World War.
“The various finds mean that [officers] have been able to make that connection,” said Gustafsson.
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Police have not been able to identify the bones, which were laid to rest at a low-key ceremony after the forensic investigation had been concluded.
“You bury them on the site where you find them. Exactly what that means I dare not say, but you conduct some kind of ceremony where you bury the remains together with other things found at the scene. It's fitting to do that, I think. It's done with dignity,” he told the regional GT tabloid.
Although Sweden did not take part in the Second World War, remains from foreign soldiers as well as sailors who died at sea occasionally resurface on the country's beaches.
Two years ago a man found 400-year-old remains buried on a beach in southern Sweden. The bones were believed to be those of a soldier who died during the Danish occupation of Sweden in the 1600s.
And last summer a woman in other parts of southern Sweden made headlines after she stumbled upon scores of skulls and human bones inside Ikea bags in a church.
An archaeologist told The Local at the time that he had been tasked with documenting and reburying the up to 500-year-old bones, but that the project had been delayed.