Switzerland will declassify the archival dossier on Nazi criminal Josef Mengele

The Swiss Federal Intelligence Service (NDB) announced on Monday, May 4, the decision to open public access to the archived file of Nazi doctor Josef Mengele. Access will be provided subject to conditions and restrictions yet to be determined.

The decision was the result of a legal complaint by historian Gerard Wettstein, who challenged the intelligence service’s refusal to provide documents. Previously, the NDB had rejected all requests, citing an 80-year access limitation period. The last time a request for access was rejected was in February 2026.

Watson.ch writes that the intelligence service has now admitted that access to the dossier should be open. In 2001, the Swiss government decided that archival material examined by the independent Bergier Commission as part of its investigation into the country’s role during the Nazi era should generally be open to the public. The Federal Archives confirmed that Mengele’s dossier fell into this category. NDB intends to use this case to review its general policy on access to classified archives.

The dossier is of particular interest to researchers as it may contain information about Mengele’s stay in Kloten (canton of Zurich) in March 1961 and answer the question of how an international wanted war criminal was able to leave Switzerland without hindrance.

Mengele served as an SS doctor at the Auschwitz death camp, where he selected prisoners, sending hundreds of thousands of people to gas chambers, and performed savage medical experiments on prisoners, including twins. After the war, he fled to South America and in 1979 drowned while swimming in Brazil, where he was living under an assumed name.

About a year ago, the German public broadcaster MDR discovered a police dossier on Mengele that was thought to be lost in Argentine archives. The documents contained detailed information about his stay in Argentina and, in particular, showed that in 1959 he applied to enter the Federal Republic of Germany under his own name. This fact was previously unknown to researchers.