Switzerland's Federal Intelligence Service will open its long-sealed file on Josef Mengele, the Auschwitz doctor known as the 'Angel of Death', after years of denying historians access. The dossier, held in the Swiss Federal Archives, may shed light on whether Mengele was present in Switzerland in 1961 and how authorities responded to one of the world's most wanted Nazi war criminals.

The agency said access will be granted under conditions to be defined later, following a reassessment of the file's classification. The decision also signals a broader review of policies governing access to classified archival records, particularly those connected to Switzerland's actions during the Second World War.

Mengele carried out mass killings and brutal medical experiments at Auschwitz before fleeing to South America, where he died in 1979 without facing trial. The move to release the file comes after a legal challenge by historian Gérard Wettstein and aligns with a government policy favoring greater transparency regarding historical records reviewed by an independent commission examining Switzerland's wartime conduct.