Josef Mengele—Willem Sassen

Josef Mengele—Willem Sassen is a relationship shaped first by recognition and mutual trust, then by a breach with practical consequences. In Buenos Aires, the two men meet through the city’s Nazi press network. Sassen becomes one of the few people to whom Mengele reveals his real identity and history; later, when Mossad offers money, Sassen helps uncover where Mengele has fled and who is sheltering him. Their connection links the fugitive’s carefully guarded private world to the information that brings the pursuit close to him.

Meeting in Buenos Aires

Mengele encounters Sassen at a Buenos Aires journal that serves as a gathering place for Nazis. He already knows Sassen’s writing and recognizes him as the newspaper’s gifted craftsman, while Sassen has established himself as a journalist and a figure with useful connections. Their first encounters are wary rather than immediately intimate: the two men assess one another, and their shared past in the SS provides a basis for recognition. Sassen had volunteered for the SS and fought on the Russian front, where he was badly injured. After the war, he was imprisoned in the Netherlands, escaped twice, reached Ireland, and eventually sailed to Argentina.

The resemblance between their paths does not make them identical. Sassen had worked as a propagandist for the Third Reich and was a high-level collaborator; Mengele, for his part, is presented as someone who sought the company of influential men rather than ordinary SS members. He cultivated chiefs and camp commandants and disdained mediocrity. Sassen’s writing, bearing, fluency, and network of acquaintances suit that preference. Their friendship develops within an expatriate milieu built around former Nazis and collaborators, but the account makes their mutual appraisal personal: they sniff each other out before trust takes hold.

Trust, access, and a warning

Sassen’s discretion becomes decisive when Mengele confides his true identity and history. The disclosure marks a change in their relationship: Mengele has arrived in Buenos Aires under an assumed identity, but with Sassen he allows the concealed past to be spoken. Sassen’s social reach helps explain why Mengele values him. He has learned Spanish with striking speed, built a place for himself in Argentina, and impressed Mengele with his address book. He also offers access to other powerful or well-connected figures, including Hans-Ulrich Rudel, for whom he sometimes serves as driver and ghostwriter.

The connection is also practical. Sassen proposes introductions and opens doors into a network of prominent German refugees; through him, Mengele is brought toward gatherings where figures such as Rudel and Gerard Malbranc are present. At one meeting, Sassen takes Mengele by the arm and says he wants to introduce him to two friends. The gesture captures Sassen’s role as intermediary: he does not merely share company with Mengele but helps place him within a wider circle of contacts.

That same access makes Sassen a potential source of danger. In 1957, he hosts recording sessions with Adolf Eichmann, who speaks at length about his past. Sassen presses Mengele to participate, but Mengele refuses. He regards Eichmann as a boastful and embittered man whose public claims could expose the group. Mengele warns Sassen that Eichmann’s name is already in the press, that German authorities are pursuing him, and that the pseudonym Klement may not protect his identity if he continues talking. Mengele wants no publicity and has other priorities. His refusal shows the limits of the friendship: he trusts Sassen with his own secret, but does not accept Sassen’s judgment about a project he considers hazardous.

Estrangement and betrayal

By early 1958, the Nazi publishing circle in Buenos Aires is coming apart. Eberhard Fritsch closes his publishing house and leaves for Austria, while Sassen tries to sustain himself through journalism under different pseudonyms. Mengele responds by distancing himself from both Sassen and Eichmann. He considers the men drawing-room Nazis and advises others in Buenos Aires to avoid Eichmann, whom he regards as dangerous. The friendship has not simply vanished, but its terms have narrowed: Mengele withdraws from Sassen’s circle and refuses the exposure that Sassen’s recordings invite.

The decisive rupture comes in the spring of 1962. Sassen, then in Uruguay, approaches Mossad prepared to give information about his former friend. The narrative attributes his action principally to the need for money to maintain an expensive lifestyle and support his mistresses, while also noting that he presents it as a response to what he considers an affront to the SS’s honour. Mossad pays him. Sassen has lost track of Mengele, but he learns that the fugitive has gone to Brazil and identifies Wolfgang Gerhard as his new protector and principal contact with the outside world.

This is not a simple, immediate handover of Mengele’s location. Sassen supplies a lead about the flight and the person protecting him; Mossad agents then keep Gerhard under observation. One morning, Gerhard’s Ford Anglia heads out across the savannah toward an isolated farm. The information Sassen provides has turned an old friendship into a route for surveillance, even though the pursuit still depends on further observation and confirmation.

The friendship’s consequence

At the farm, Zvi Aharoni and two agents meet three men during a picnic nearby. One, of European appearance, wearing a hat and moustache, stays back while his companions speak Portuguese. Aharoni believes the silent man is Mengele, but he does not act on recognition alone: he keeps his composure and wants another unit to photograph the suspect before the operation proceeds. The episode gives Sassen’s betrayal a concrete consequence. His disclosure helps bring the search to the fugitive’s refuge, but it does not itself secure an arrest.

The relationship therefore joins two different forms of secrecy. For a time, Mengele entrusts Sassen with the identity he hides from the wider world; later, Sassen converts what he knows into intelligence for the pursuers. Their shared history and access to the same political network first make confidence possible and then make its breach consequential. The narrative’s emphasis falls not on a dramatic confrontation between the former friends, but on the change in the use of knowledge: what had been entrusted privately becomes a lead in an international hunt.