The United States feared the spread of communism by the Russians in post-World War II so much that they recruited as many as 1,000 ex-Nazis to serve as spies against the Eastern front.

"This all stemmed from a panic, a fear that the Communists were terribly powerful and we had so few assets," Richard Breitman, a Holocaust scholar at American University, told The New York Times.

Classified records kept the extent of the Nazis used by U.S. intelligence agencies hidden to the public as recently as the 1990s, according to The New York Times. Evidence of the Nazis employment first emerged in the 1970s and then thousands of more records were declassified under the Freedom of Information Act.

The American military, the C.I.A., the F.B.I. and other agencies all used the ex-Nazis as spies and informants. The number of Nazis who escaped persecution for their war crimes and joined the spy agencies may go higher than 1,000, but some records remain sealed, according to the Times. None of the spies are believed to be alive today.

"U.S. agencies directly or indirectly hired numerous ex-Nazi police officials and East European collaborators who were manifestly guilty of war crimes," Norman Goda, a University of Florida historian on the declassification team, told the Times. "Information was readily available that these were compromised men."

Aleksandras Lileikis, a Nazi collaborator that the U.S. relocated to Boston, may have been involved in the machine-gun massacre of 60,000 Jews in Lithuania. Another SS officer, Otto von Bolschwing" served as a top aide to Adolf Eichmann, the architect of the "Final Solution," and wrote policy papers on how to "terrorize Jews," according to the Times. The C.I.A. hired Bolschwing to spy in Europe and later relocated him and his family to New York City in 1954.

Many of the Nazi spies ended up being "habitual liars, confidence men or embezzlers," according to the Times. Some also worked as double agents for the Soviets.