Raoul Wallenberg has been declared officially dead by Sweden's Tax Agency, 71 years after his disappearance. The Swedish diplomat became famous for saving thousands of Hungarian Jews from the concentration camp in Auschwitz during the Second World War by providing them with protective passes.

Fondly known as "Swedish Schindler", Wallenberg was arrested by Soviet forces in Hungary in 1945 while working as Sweden's special envoy in Budapest during the war. Little is known about his life, aside from a few prison records and a sense of mystery has come to surround his existence post imprisonment. However, former Soviet authorities suspect that he probably died in prison in Moscow around 1947.

According to a 1947 statement by prison doctor Colonel Alexander Smoltsov, the 34-year-old Swede died from a heart attack on 17 July, but KGB reports state that he was questioned in Moscow's Lubyanka prison on 23 July 1947.

His family had spent years attempting to find out what happened to him, but in November 2015 a representative applied for Wallenberg's death certificate via Sweden's SEB Bank.

"The official date of his death is 31 July 1952," said Pia Gustafsson, an official from the Swedish tax authority that registers birth and deaths. "This date is purely formal. Legally, we must choose a date at least five years after his disappearance and there were signs of life until the end of July 1947."

The Wallenberg family released a statement last year explaining that the "declaration of death is a way to deal with the trauma we lived through, to bring one phase to closure and move on".