Argentina tracked Josef Mengele for years but let him slip away, documents reveal

Authorities in Argentina knew the true identity of Dr. Josef Mengele, the notorious Nazi doctor who fled to the country and hid in plain sight after the second world war, according to documents newly opened on the orders of President Javier Milei.

Known as the Angel of Death, Mengele carried out horrific experiments on prisoners, including twins, under the pretense of medical research, and sent countless Jews to their deaths in gas chambers.

Documents hidden for decades reveal that he lived quietly in hiding in Argentina after his escape from Germany 1949, using an Italian passport in the name of Helmut Gregor.

In April 2025, at the urging of the Simon Wiesenthal Centre, Milei announced the release of nearly 1,850 classified documents that show how Nazi fugitives escaped to the country via ‘rat-lines’ after World War II.

This latest bombshell discovery reveals how Argentine authorities tracked Mengele’s life across South America during the 1950s, yet never arrested him.

Mengele studied philosophy in Munich in the 1920s, where he became a fervent Nazi, later studying medicine in Frankfurt. In 1933 he joined the SA (Sturmabteilung), the Nazi party’s paramilitary wing and began working at its research institute to study heredity and so-called racial purity.

At the start of the war he served as a medical officer in the Waffen SS.

From 1943 to 1945, he was chief physician at Birkenau, the extermination camp next to Auschwitz, and selected detainees arriving by train either for slave labour or for the gas chambers.

After the liberation of Auschwitz, Mengele was transferred to the Mauthausen concentration camp. He vanished when it was liberated, apparently then spending several years in Bavaria before reaching South America in 1949, with an Italian passport under the name Helmut Gregor, to begin a new life there.

By the mid-1950s, the newly declassified documents show that Argentine authorities knew exactly who ‘Helmut Gregor’ was and what he was responsible for, yet did nothing.

The New York Post reports that newspaper clippings in the newly opened dossier include an undated interview with one of Mengele’s victims, Jose Formanski, who said: “He gathered twins of all ages in the camp and performed experiments on them that always ended in death. Children, elderly people and women, what horrors.”

In 1956, Mengele asked the West German Embassy in Buenos Aires for his original birth certificate and actually began using his real name. He also requested that his identity papers be reissued.

A document written by officials a year later recorded Mengele’s explanation for entering Argentina under an alias, reporting: “He said that during the war he served as a doctor in the German SS in Czechoslovakia, where the Red Cross called him a war criminal.”

The papers show that Argentine law enforcement agencies knew Mengele was living in Carapachay, a town on the outskirts of Buenos Aires, and that he had married his brother’s widow during that period. They also indicate authorities were aware that his father visited him, possibly to invest in Mengele’s new medical business.

In 1959, West Germany issued an arrest warrant for Mengele and sought his extradition, but a local judge rejected the request, claiming it was based on “political persecution.”

The failed extradition attempt led to international pressure on Argentina, and Mengele fled to Paraguay, where he obtained citizenship. By the time Argentinian  authorities finally raided his medical laboratory in Buenos Aires, he had already disappeared.

Around 1960, Mengele was tracked to Brazil, where he was being sheltered by farmers of German descent.

He is believed to have drowned at the age of 67, after having a stroke while swimming near the coastal town of Bertioga in 1979.

While he was initially buried under a false name, an investigation led to his exhumation in 1985 and today his bones are used for forensic medicine training at the University of Sao Paulo’s medical school.

After World War II, Argentina also gave refuge to senior Nazi Adolf Eichmann. Captured there by Israel’s Mossad in 1960, he was subsequently tried in Israel and executed.

The newly declassified materials are now based in Argentina’s General Archive of the Nation and will be made available for both public and academic research.