A Nazi doctor known for barbaric prisoner experiments and handpicking gas chamber victims led a carefree post-war life in Argentina – despite authorities knowing his true identity, declassified documents revealed..

Coldblooded SS Commander Josef Mengele aka “The Angel of Death” gleefully oversaw the horrific torture of Jews and other prisoners at Auschwitz concentration camp under the guise of medical research before he fled Germany for Argentina in 1949.

He escaped justice under an assumed name just as the Nuremburg trials exposed his crimes.

Bombshell intelligence files, recently declassified by Argentinian President Javier Milei, detail how Argentinian authorities tracked Mengele’s life across South America but never apprehended him, Fox News Digital’s Solly Boussidan reported.

Newly declassified documents reveal how Nazi war criminal Josef Mengele was able to evade capture and live in the South American country. AP

At times, the press tipped Mengele off, or top-down decisions were simply made too late.

The then Argentinian government was known for harboring Nazis, and allowing an underground community to prosper, according to Reuters. Surveillance reports, immigration records, and intelligence briefs paint a picture of fractured law enforcement efforts, which the twisted Nazi doctor was able to evade.

Mengele entered Argentina to begin in 1949 with an Italian passport under the name Helmut Gregor. There, he began a new life.

By the mid 1950s, documents prove Argentinian authorities knew the ‘Angel of Death’ was among them, according to an-depth analysis of the Spanish language records by Fox.

A Federal Police bulletin ordering the capture of Mengele in 1960. General Archives of the Government of Argentina

The cover of set of documents on the investigation into Mengele in Argentina. General Archives of the Government of Argentina

Newspaper clippings in the file include a chilling undated interview with one of Mengele’s victims, José Furmanski.

“He gathered twins of all ages in the camp and subjected them to experiments that always ended in death. Between the children, the elderly, and women… what horrors,” Furmanski said in the interview.

A record sheet for the issuing of an ID card by the Federal Police to Mengele under the false name Gregor Helmut in 1949. General Archives of the Government of Argentina

A record sheet for the issuing of an ID card under Mengele’s real name in 1956. General Archives of the Government of Argentina

In 1956, Mengele requested his original birth certificate from the West German Embassy in Buenos Aires and had shockingly begun using his real name, requesting identification cards be reprinted.

A memo written by officials a year later says Mengele “explained” why he originally entered Argentina under a fake name.

An envelope with photos of Mengele kept by Argentine intelligence General Archives of the Government of Argentina

An envelope containing records of Mengele’s fingerprints. General Archives of the Government of Argentina

“He (Mengele) demonstrated being nervous, having stated that during the war he acted as a physician in the German S.S., in Czechoslovakia, where the Red Cross labeled him a ‘war criminal,’” read the memo.

Argentine agencies knew Mengele lived in Carapachy, a town on the outskirts of Buenos Aires, and that he had married his brother’s widow at the time, the documents showed. Authorities were even aware his father had visited, perhaps to invest in the twisted doctor’s new medical business, documents showed.

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In 1959, West Germany issued an arrest warrant for Mengele, requesting his extradition, but a local judge denied the warrant, saying it was based on “political persecution.”

The failed extradition led to international pressure on Argentina, and Mengele fled to Paraguay where he was granted citizenship, according to the records. When Argentinian authorities finally raided his medical laboratory in Buenos Aires, the Nazi was long gone.

Mengele (second from left) seen with other Nazi SS officers near Auschwitz in May 1944. AP

After his escape, the documents indicate Argentinian authorities relied heavily on foreign news reports to track Mengele. Around 1960, the twisted doctor eventually found safe harbor in Brazil, where he was protected by farmers of German descent.

Mengele died after suffering a stroke while swimming near the coastal town of Bertioga. He was buried under a false name, but an investigation led to his body being exhumed in 1985. Today, his bones are used to teach forensic medicine at the University of Sao Paulo’s Medical School.