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Swiss intelligence to release long-sealed Mengele files
The Swiss Federal Intelligence Service announced this month it will grant access to classified documents on Josef Mengele, the infamous Nazi doctor known as the "Angel of Death," though no timeline or conditions for the release have been disclosed.
Mengele's ties to Switzerland: A lingering mystery
Mengele, who conducted horrific medical experiments on prisoners at Auschwitz, fled Europe in 1949 using Red Cross travel documents obtained under a false identity. While he spent most of his post-war life in South America, rumors have persisted about his presence in Switzerland.
In 1956, Mengele and his son Rolf took a skiing holiday in the Swiss Alps-a fact known since the 1980s. However, historian Regula Bochsler uncovered evidence suggesting he may have returned in 1961, after an international arrest warrant was issued. That year, Austrian intelligence warned Swiss authorities that Mengele might be traveling under an alias in Switzerland.
Meanwhile, Mengele's wife rented an apartment in Zurich, applying for permanent residency. The modest flat, near the international airport, was placed under police surveillance in 1961. Officers noted her driving a Volkswagen with an unidentified male passenger-but whether it was Mengele remains unconfirmed.
Decades of secrecy fuel suspicion
Swiss authorities have repeatedly denied historians access to Mengele's files, citing national security and the protection of his extended family. The documents were sealed until 2071, sparking accusations of a cover-up.
In 2019, Bochsler's request to view the files was rejected. In 2025, historian Gérard Wettstein challenged the decision in court, crowdfunding 18,000 Swiss francs (£17,000; $23,000) to cover legal costs. Only after his appeal did the Federal Intelligence Service agree to release the files-though with unspecified "conditions and requirements."
"As long as they are closed until 2071, it fuels conspiracy. Everyone says, 'They must have something to hide.'"
Gérard Wettstein, historian
What might the files reveal?
Some experts doubt the documents will contain significant evidence about Mengele's presence in Switzerland. Sacha Zala, president of the Swiss Society for History, believes the files may reference foreign intelligence contacts, such as Israel's Mossad, which tracked Nazi fugitives in the 1950s and 1960s.
"It shows the stupidity of the declassification process without historical knowledge," Zala told the BBC. "The administration fueled conspiracy theories."
Jakob Tanner, a historian who served on the 1990s Bergier Commission investigating Switzerland's wartime role, argues the secrecy reflects broader national sensitivities. "It's a conflict between national security and historical transparency," he said. "The former often prevails in Switzerland."
Tanner also finds it plausible Mengele visited Switzerland in 1961. After Mossad captured Adolf Eichmann in Argentina in 1960, other Nazis feared they were next and may have sought refuge in Europe. Walter Rauff, another wanted war criminal, traveled to Germany in 1960.
Uncertainty remains over redactions
A historian on the Bergier Commission briefly reviewed some Mengele files in 1999 but could neither confirm nor deny his presence in Switzerland. The documents were resealed, and the historian later died.
Wettstein fears the files will be heavily redacted. "I fear we will get a file that is more black than transparent," he said. Bochsler echoed his concerns: "I don't trust [the authorities] at all. Why have these files been closed for so long?"
A legacy of evasion and unanswered questions
Mengele evaded justice throughout his life, dying in Brazil in 1979 under a false name. His body was exhumed in 1985, and DNA testing in 1992 confirmed his identity. Yet questions about his possible ties to Switzerland persist.
"Maybe we will never get to the real truth," Wettstein said. "We will never know if he was here or not... but maybe we can have at least a clearer idea."
