Nina Viveka Maria Lagergren (née von Dardel; 3 March 1921 – 5 April 2019) was a Swedish businesswoman and the half-sister of Raoul Wallenberg, and the leading force to find out what happened to him after his disappearance.

[3][4] Lagergren was the presenter of an episode of Sommar i P1 at Sveriges Radio on 4 August 2014 where she told about her life and her work to find out what had happened to her half-brother.

[5] On 8 March 1945, Soviet-controlled Hungarian radio announced that Wallenberg and his driver had been murdered on their way to Debrecen, suggesting that they had been killed by the Arrow Cross Party or the Gestapo.

[6] Sweden's foreign minister, Östen Undén, and its ambassador to the Soviet Union, Staffan Söderblom, wrongly assumed that they were dead.

While in the transit camp in Kirov, while being moved to Vorkuta, Dufving encountered a prisoner dressed in civilian clothes with his own special guard.