Mossad’s pursuit of Mengele and its repeated interruptions

Mossad’s pursuit of Mengele was a sustained but repeatedly interrupted effort to locate and capture a fugitive whose aliases, cross-border protectors, and sudden moves kept him just ahead of the agency. In 1960, its director, Isser Harel, planned to use the operation to bring Mengele from South America to Israel alongside Eichmann. Agents reached the address where they believed Mengele’s family had stayed, but found that he had already vanished. A later investigation brought Mossad close to identifying him in Brazil; then the agency suspended the hunt to pursue Yossele, and its priorities shifted again toward the threat posed by German rocket specialists in Egypt.

A target in Eichmann’s shadow

By 1960, Harel was secretly planning to add Mengele to the investigation that had led to Eichmann. The intelligence on Mengele was scattered and outdated: he was known by the name Gregor and was thought to run a furniture factory in central Buenos Aires. Harel’s plan depended on timing. After Eichmann’s scheduled seizure on 11 May, Mossad would have nine days to find Mengele and bring him to the plane carrying Eichmann to Israel. Harel carried Mengele’s coded file in his luggage as commandos arrived in Buenos Aires in early May.

After Eichmann was seized, Israeli agents questioned him about Mengele’s location, appearance, habits, and associates. Eichmann initially refused to betray his former comrade, but eventually gave the agents the address of a guesthouse in Vicente López. Harel sent two agents to investigate the isolated villa. Its manageress did not recognize either Gregor or Mengele; a postman supplied the more useful lead, saying that a Mengele family had lived there but left weeks earlier without giving a forwarding address. The furniture factory offered no confirmation of the name Gregor. By the time Mossad reached these locations, Mengele had left Argentina for Paraguay.

The agents considered raiding the guesthouse, but were warned that doing so could ruin the operation. Their caution reflected the surrounding danger: Eichmann’s sons were searching for their father and coordinating with Sassen, while Nazi networks in Buenos Aires were alert. On 20 May, Eichmann was flown from Buenos Aires to Tel Aviv. Harel promised his men that Mengele would remain a target and that a special unit would be created to track Nazi fugitives. The planned link between the two men’s captures had failed, but the agency’s pursuit of Mengele did not end with Eichmann’s departure.

Renewed surveillance and a near identification

In September 1960, as Mossad’s special unit monitored the movements of Mengele’s wife and son and approached Krug’s farm, Mengele decided to disappear again. He destroyed papers and specimens, separated from his family, and crossed into Brazil with help from Rudel and Krug. The move broke the trail Mossad had been following in Paraguay. It also meant that the agency’s next effort would have to reconstruct his contacts and whereabouts across national borders.

Under Zvi Aharoni, the unit established a headquarters in Paris and pursued leads through South America. The family network in Günzburg proved difficult to penetrate, Krug’s relatives were suspicious, and an attempt to approach one of his daughters through an agent made little progress. Aharoni sent agents to Paraguay, where Mossad believed Mengele might have returned after learning of his Paraguayan citizenship. The agency also followed Rudel, intercepted Martha’s mail, and tried to enter German community institutions in Asunción. These inquiries increased pressure but did not locate Mengele, who remained a step ahead.

In the spring of 1962, Sassen supplied a decisive lead. He had lost contact with Mengele but identified Brazil as his destination and named Wolfgang Gerhard as the fugitive’s protector and principal link to the outside world. Mossad followed Gerhard to an isolated farm. Aharoni and two agents who were Brazilian Jews went to the vicinity on a picnic, where they watched three men approach. One, wearing a hat and keeping apart from his companions, matched the figure Aharoni suspected was Mengele. Aharoni did not act on recognition alone: he wanted another unit to photograph the man and confirm his identity without alerting the farm. He returned to Paris to prepare a more difficult operation, but that confirmation and operation would not follow.

Operation Tiger suspends the hunt

Back in France, Aharoni was ordered by Harel to stop the Mengele investigation and help find Yossele, an eight-year-old boy whose disappearance had become a source of acute conflict in Israel. Yossele’s ultra-Orthodox grandfather had refused to return him to his secular parents, and the boy had subsequently vanished. As public tensions mounted, David Ben-Gurion ordered Mossad to intervene. Aharoni’s team was redirected from a fugitive Nazi in Brazil to a missing child whose case had become a domestic political crisis.

Operation Tiger required agents to infiltrate religious communities in Europe, the United States, and South America. The search eventually located Yossele living with an ultra-Orthodox family in Brooklyn; he was brought back to Israel. The operation lasted eight months and cost Mossad one million dollars. During that interval, Mengele moved again. The interruption was therefore more than a delay in the same investigation: when the agency returned its attention to him, the Brazilian lead was no longer enough to secure his capture.

Strategic priorities displace the pursuit

Mossad’s resources and leadership were soon drawn toward a different perceived danger. German scientists and technicians were advising Egypt’s missile programme, and reports warned that the weapons under development might threaten Israel. Harel launched Operation Damocles against the German specialists. The covert campaign led to letter bombs, kidnappings, and killings, and a threat against the daughter of a West German expert ended with Israeli agents arrested in Switzerland. The ensuing public scandal endangered relations between West Germany and Israel and helped force Harel’s resignation.

His successor, Meir Amit, did not make the hunt for Nazi fugitives a priority. Mossad was directed toward intelligence-gathering and the conflict with Israel’s Arab enemies, while Israel prepared for the Six-Day War. Mengele’s capture receded into the background. By the middle of 1963, Mengele learned through Gerhard that investigators had left Günzburg and that Martha was no longer being followed in Merano. The pause in pressure gave him reason to believe that his pursuers had again turned elsewhere, though it did not mean that he had been found innocent or that the earlier investigations had disproved his identity.

A pursuit limited by borders and interrupted attention

Mossad’s failures to capture Mengele arose from a combination of factors rather than one lost lead. In 1960, outdated information sent agents to addresses he had already left. His flight from Paraguay changed the geography of the search, while his protectors and family connections made surveillance difficult. Aharoni’s Brazilian observation offered a promising identification, but the agency’s order to find Yossele interrupted the work before it could become an operation. The later focus on Egypt’s missile programme and the leadership change after Operation Damocles displaced the pursuit again.

The broader international setting also constrained the hunt. Mengele’s movement between Argentina, Paraguay, and Brazil exploited borders and competing jurisdictions, while his Paraguayan citizenship complicated efforts to secure extradition. West German authorities proceeded slowly and concentrated their search in Paraguay, even though information indicated that he had gone to Brazil. Mossad’s investigations could bring agents close to Mengele, but proximity did not itself overcome the need for reliable identification, sustained resources, and a decision to act. The relationship remained one of repeated pursuit and interruption: the agency returned to his trail more than once, yet each time he or its priorities moved before capture could follow.