Switzerland’s federal intelligence agency said it would finally make public long-sealed documents about notorious Nazi war criminal Josef Mengele, but gave no details on when.
Mengele fled Europe after World War II but has been rumored to have spent time in Switzerland for years, despite an international arrest warrant being issued.
Historians have repeatedly requested access to the archives, but Swiss authorities have so far refused.
Mengele was a doctor who served in the German Waffen SS. He was sent to the Auschwitz extermination camp in Nazi-occupied Poland, where he selected those to be sent to the gas chambers—an estimated 1.1 million people died, including about 1 million Jews.
Known as the “Angel of Death,” he also selected prisoners (mainly children and twins) for sadistic medical experiments of questionable value before sending them to death.
After the war, Mengele, like many high-ranking Nazis, quickly changed his uniform and name.
Using a false identity, he obtained Red Cross travel documents at the Swiss Consulate in Genoa, northern Italy, and used them to flee to South America.
The Red Cross aimed to provide the documents to thousands of people across Europe who had been displaced or stateless by the war, but Nazis seeking to evade prosecution also managed to obtain them, for which the Red Cross later apologized.
The ICRC office in Genoa issued these passports under false names to Nazi war criminals (left to right) Josef Mengele, Klaus Barbie and Adolf Eichmann [AFP via Getty Images]
So what does Mengele have to do with Switzerland?
Although Mengele fled Europe in 1949, he went on a skiing holiday in the Swiss Alps in 1956 with his son Rolf. This information has been known since the 1980s.
Officially, he spent the rest of his life in South America.
But Swiss historian Regula Bochsler has long wondered whether Mengele ever returned, crucially after an international arrest warrant was issued in 1959.
While researching Switzerland’s possible role as a transit country for fleeing Nazis, Bochsler discovered that in June 1961, Austrian intelligence warned the Swiss that Mengele was traveling under an assumed name and might be on Swiss soil.
“There appears to be evidence that Mengele planned a trip to Europe in 1959. Why did Mrs. Mengele rent an apartment in Zurich?”, Source: Regula Bochsler, Source description: Swiss Historian, Photo: Historian Regula Bochsler
Meanwhile, Mengele’s wife rented an apartment in Zurich and applied for permanent residency.
“There seems to be evidence that Mengele planned to travel to Europe in 1959,” the historian told the BBC. “Why does Frau Mengele rent an apartment in Zurich?”
The apartment was in a modest suburb where the Mengele family had enough wealth to buy something fancier. But it’s very close to the international airport.
Boxler was able to see Zurich police files proving that the apartment was under surveillance in 1961; the police even noticed Mrs. Mengele driving her Volkswagen with an unidentified man beside her.
But is this her husband?
Mengele (centre) with Auschwitz commander Richard Bell (left) and former commander Rudolf Hoss in 1944 [Universal History Archive]
The arrest of a wanted war criminal, as was the case with Mengele in 1961, requires the involvement of the Swiss Federal Police. In 2019, Boxler applied to the Swiss Federal Archives to see their files.
She was rejected. For national security reasons and to protect the extended family, the documents have been sealed until 2071.
Boxler isn’t the first or last to be rejected. In 2025, historian Gérard Wettstein tried again. He was also rejected.
“It seems ridiculous,” he told the BBC. “As long as they’re closed until 2071, it feeds the conspiracy and everyone says ‘they must have something to hide’.”
Wetterstein challenged the Swiss authorities’ decision and took them to court, a costly process for which he sought crowdfunding. “We raised 18,000 Swiss francs (£17,000; $23,000) in just a few days.”
Mengele is pictured with an unidentified woman in the 1970s in Brazil, where he lived for decades [Robert Nickelsberg / Getty Images]
That’s when the Swiss Federal Intelligence Service finally changed its mind. In a statement this month, it suggested full transparency may take some time, saying: “The appellant will be granted access to the file, but the conditions and requirements have not yet been determined.”
Not everyone is convinced the documents will reveal more about Mengele himself.
Sacha Zala, president of the Swiss Historical Society, is “absolutely certain that Mengele had nothing to do with it,” but believes that foreign intelligence agencies or foreign informants may have been involved.
By the late 1950s, Israel’s Mossad was actively tracking escaped Nazi war criminals, and Zara suspected they might have connections to the Swiss. This would give Swiss authorities reason to seal documents, as sensitive information related to foreign intelligence agencies is often redacted.
But is it really that sensitive to merely mention the Mossad’s famous hunt for Nazis 70 years ago?
“This shows the folly of the declassification process without historical knowledge,” Zara believes. “In this way, the government promotes conspiracy theories.”
Other historians, such as Jacob Tanner, say the secrecy of the archives reveals more about Switzerland than they do about Mengele. “This is a conflict between national security and historical transparency, with the former often dominating in Switzerland.”
Historian Gerard Wetterstein successfully challenges Swiss Federal Archives’ decision to keep Mengele files secret (after his death) [BBC]
Tanner served on the Bergill Commission in the 1990s, which examined neutral Switzerland’s relations with Nazi Germany, particularly the role of Swiss banks.
He was intimately familiar with Switzerland’s sensitivity and shame over its role in World War II, when Jewish refugees were turned away at the border and Swiss banks retained the money of Jewish families who later died in Nazi concentration camps. “It’s a problem for democracies that these files remain closed,” Tanner argued.
Nonetheless, he considers the possibility that Mengele was in Switzerland in 1961 to be reasonable.
In 1960, wanted Nazi war criminal Adolf Eichmann was captured by the Mossad in Argentina, and there was evidence that other Nazis who fled to South America believed they too were in danger there, while Europe, where friends and relatives remained, might be safer.
Tanner noted that Walter Rauff, another Nazi war criminal who fled to Chile, spent 1960 in Germany.
In 1999, a historian from the Bergier Commission was allowed to briefly look at some of Mengele’s archives and concluded that it was impossible to prove or disprove his presence on Swiss soil. But this is just a few lines from a 24-volume report on the entire war. The archives were sealed again; the historian died seven years ago.
Meanwhile, a release date for the documents has not yet been set, and the BND’s statement on “conditions and requirements” sounds ominous to Wetterstein. “I’m worried we’re going to get a document that’s darker than transparent,” he said.
Boxler is also concerned that the documents will be heavily redacted. “I don’t believe [the authorities] Not at all. I’m worried it’s going to look like the Epstein files. Why were these Mengele files closed for so long? “
Mengele has been the subject of mystery, rumor and conspiracy for decades.
He was never arrested, let alone convicted, for his horrific crimes. When he died in Brazil in 1979, he was buried under an assumed name.
But the rumors continue. His body was exhumed in 1985, and DNA testing finally confirmed it was his in 1992.
The terrible doctor at Auschwitz died.
But has he been to Switzerland? Did the Swiss just not notice him?
Are they turning a blind eye to the presence of potential embarrassment to avoid the unwelcome attention an arrest might bring? Or, like so much about Mengele, was it all just a rumor?
“Perhaps we will never know the true truth,” Wetterstein said. “We’ll never know if he was here…but maybe we can at least have a clearer idea.”
