Switzerland released the Mengele file redacted. Historians speak of a scandal and want to take it to court

At the end of June, we wrote that Switzerland is opening a secret file on Josef Mengele after decades, and we quoted the fear of a historian who had sued to obtain access: that the documents would arrive "more black than transparent." On Wednesday afternoon, the Zurich newspaper Tages-Anzeiger reported that the federal intelligence service had released the file only in redacted form. According to the newspaper, historians speak of a scandalous procedure that damages Switzerland's reputation, and want to take the matter to court. Tages-Anzeiger ↗

What's new here

The disclosure itself is not news — we wrote about that in the June article. What's new is the condition the file ultimately arrived in. Tages-Anzeiger published this on Wednesday around five in the afternoon, and at the time of writing, no other Swiss or Slovak site had the story in its coverage. We were therefore unable to independently verify the extent of the redaction — how many pages and which passages — and we do not state it in the text below. Tages-Anzeiger ↗

The agency said in advance that it would be redacted

This is a part you can read straight from the official document. In its communiqué of May 4, the NDB announced that it would grant access to the file at the Swiss Federal Archives, but "under conditions still to be specified" — and immediately added why: the documents still contain information worth protecting, specifically source data and information from partner services. So the redaction was no surprise; it was announced four months in advance. VBS/NDB ↗

The same communiqué also makes the file's origin clear. It was opened by the Police Service of the Federal Prosecutor's Office, the predecessor of today's intelligence service, and was transferred to the archive in 2001. The legal basis for the disclosure is a federal government resolution of December 7, 2001, which mandates a "liberal practice of access" to materials examined by the Bergier Commission — and the Federal Archives confirmed that the Mengele file is among them. VBS/NDB ↗

This was preceded by a refusal. Wettstein requested the file at the end of 2025, the NDB turned him down in February 2026 citing source protection, and the historian turned to the Federal Administrative Court in St. Gallen. He funded the lawsuit through a fundraiser that collected around eighteen thousand francs within a few days. Only then did the agency reconsider the legal situation. SRF ↗

What historians are looking for in the file

The question is narrow and specific: was Mengele still in Switzerland after the war, despite an international arrest warrant against him in effect since 1959, and did the authorities there let him leave? It is documented that in 1956 he went skiing with his son in Engelberg. Five years later, his wife rented an apartment in Kloten near the airport and applied for a residence permit, while police recorded her driving a Volkswagen with an unknown man. t-online ↗

Historian Regula Bochsler found clues that may point to a further stay around 1961, and Austria's intelligence service warned Swiss authorities in June of that year. None of this is proof yet. An official inquiry from 1999 ended with a formulation that still stands today: it can neither be proven nor disproven that Mengele was in Switzerland. t-online ↗ 20 Minuten ↗

Why the secrecy itself is an issue

The historians' argument is not that the file definitely conceals a sensation. It is the opposite — that secrecy manufactures suspicion where there may be none. "As long as they stay locked away until 2071, it will feed conspiracy theories, everyone will say: they must have something to hide," Wettstein said back in May. Sacha Zala, chairman of the Swiss Historical Society, put it more bluntly: "The government has fed conspiracy theories this way." 20 Minuten ↗

When the decision to open the file was made in May, Christoph Heubner, executive vice president of the International Auschwitz Committee, called it a form of satisfaction for survivors. That is exactly why the redaction is sensitive in a different way than an ordinary intelligence file would be: this concerns a man whose crimes no one disputes, and an archive that was being opened after twenty-five years of refusals. Medzinárodný osvienčimský výbor ↗

What we know from this, and what we don't

We know the file was supposed to remain sealed until 2071, that it was opened only after a lawsuit and a fundraiser, and that the agency had announced in advance that it would protect sources and information from partner services. We know what historians are looking for in it, and that no one has proven it yet.

We don't know how much of the documents is actually covered, or which passages — so far that is the claim of a single newspaper, a few hours old. And we don't know whether a possible further lawsuit will change anything about it. But for a file that was supposed to remain closed for another forty-five years, even a partial opening is a step forward — the question is whether it's the kind Switzerland had in mind.

Illustrative photo: the building of the Swiss Federal Archives in Bern, where the Mengele file is stored and where it can be viewed. Photo: Sandstein / Wikimedia Commons, public domain