The Swiss Federal Intelligence Service (NDB) will grant access to the secret Josef Mengele file held at the Swiss Federal Archives (BAR), NDB announced last week.
Mengele, the doctor known as the Angel of Death, ran a system of experiments on Auschwitz camp prisoners, including severe torture of twins and people with disabilities, exploiting his professional status to advance Nazi racial theory. He evaded punishment for decades until his death in Brazil in 1979.
Although historically Mengele’s interaction with Switzerland has been considered minimal, with a skiing visit in 1956 with his son as the most prominent publicly known connection, Swiss historian Regula Bochsler told the BBC that there was some evidence he had been planning a trip to Europe, possibly including Switzerland.
Crucially, this trip would have occurred sometime in 1959, after an international warrant was issued for Mengele’s arrest.
Historian Gerard Wettstein requested the archives in 2025, seeking to find out what knowledge was available about Mengele and whether there were any indications of a stay in Switzerland.
As early as 1956, Josef Mengele spent a holiday in Engelberg together with his son. Wettstein wanted to clarify whether Mengele had also stayed in Kloten in the canton of Zurich in 1961, and whether the Swiss authorities had allowed him to leave the country despite an international manhunt.
However, all applications to access the Mengele dossier – by Wettstein and others – have been rejected until now, and Wettstein was told that the files are sealed until the year 2071.
“It seemed ridiculous,” Wettstein told the BBC. “As long as they are closed until 2071, it fuels conspiracy; everyone says ‘they must have something to hide.’”
Why the secrecy until now?
The Josef Mengele file was originally created by the police service of the Federal Prosecutor’s Office, a predecessor organization of the NDB. It was transferred to the Federal Archives in 2001. Therefore, the NDB, as the legal successor, is responsible for requests to access the file.
Since being transferred to the Federal Archives, the Mengele file has been subject to an extended protection period under archival law. Based on the Archives Act and the Intelligence Service Act, the NDB has previously rejected requests for open access – most recently in February 2026.
An appeal against this decision is currently pending before the Federal Administrative Court.
As part of the ongoing appeal proceedings, the NDB conducted several reviews and consultations, including with the Federal Archives. These consultations concluded that the Federal Council decision of 7 December 2001, which instructed federal agencies to pursue a liberal access policy for federal archive material reviewed by the Bergier Commission, should be considered in assessing the access request.
The independent Bergier commission was formed by the Swiss government in 1996 amid the World Jewish Congress lawsuit against Swiss banks accused of withholding valuables belonging to Holocaust victims.
During the current review, the Federal Archives informed the NDB that the Josef Mengele file had also been reviewed by the Bergier Commission and therefore falls within the scope of the decision.
As a result of these new circumstances, the NDB is reconsidering its February 2026 decision and has informed both the court and Wettstein that a new decision will be issued.
Since the file still contains sensitive information, the NDB is in the process of deciding the conditions for accessing it.
While NDB said Wettstein can access the file, it will be “subject to conditions and restrictions that still need to be defined.”
“Requests for access to archived documents require careful balancing between the interests of research and the public on the one hand, and existing confidentiality concerns on the other – particularly the protection of sources and information from partner intelligence services,” it said.
'The administration fueled conspiracy theories'
President of the Swiss Society for History, Sacha Zala, does not believe that there will be anything relevant about Mengele in the files, instead telling the BBC that he thinks there may be references to foreign intelligence services and informants, such as the Mossad.
“It shows the stupidity of the declassification process without historical knowledge,” Zala said. “In this way, the administration fueled conspiracy theories.”
Jakob Tanner, another historian, said that the secrecy surrounding the files represented “a conflict between national security and historical transparency, and the former often prevails in Switzerland.”
“It is a problem for a democratic state that these files are still closed,” he argued.
Wettstein and Bochsler both expressed concern that, even once the files were released, they would be heavily redacted.
“I fear we will get a file that is more black than transparent,” Wettstein said, while Bochsler compared the release to that of the Epstein files, asking, “Why have these Mengele files been closed for so long?”
“Maybe we will never get to the real truth,” says Wettstein. “We will never know if he was here or not… but maybe we can have at least a clearer idea.”
Christoph Heubner, executive vice president of the International Auschwitz Committee, thanked Wettstein for fighting for access.
“For Auschwitz survivors, even many decades after their survival, Josef Mengele remains a name that makes their hearts turn cold and sends shivers down their spines,” said Heubner.
“The fact that this very ‘Angel of Death of Auschwitz’ repeatedly escaped justice and the courts, and was able, probably for a period also in Switzerland, to live a largely relaxed and undisturbed life, still outrages and pains them to this day.
“Therefore, for Auschwitz survivors and their families, the planned opening of the Swiss files on Josef Mengele is a source of satisfaction.”
“The fact that these documents are being made public precisely at a time when Nazi perpetrators and SS criminals are being presented on Instagram without comment as ‘war heroes,’ and when the name Mengele – together with Nazi ideology of hatred and antisemitism – is gaining bizarre appeal among new Nazis and far-right extremists in many countries, is a bitter reality for Auschwitz survivors,” Heubner added.