SS Maj. Friedrich Buchardt was never called before the Nuremberg war crimes tribunal even though he was the commanding officer of one of the most ruthless killing units of Hitler's Einsatzgruppen in World War II.

A second SS figure with an equally grisly record, Brig. Gen. Franz Alfred Six, who was supposed to hunt down every official of the Soviet Communist Party if the Nazis ever got to Moscow, was called to trial but sentenced to only six years in prison. Others convicted of the same crimes were hanged.

U.S. and other allied intelligence officials may have helped Buchardt and Six escape justice in return for their collaboration after the war.

Documents recently declassified by the CIA and turned over to the National Archives identify Buchardt and Six as members of the SS "guilty of mass executions and atrocities during World War II." The documents state that Buchardt supervised the elimination of the Jewish ghetto in the White Ruthenian city of Witebsk in 1943 and that Six oversaw the murder of Jews the year before in Smolensk, just west of Witebsk.

What did Buchardt and Six trade for their freedom? Documents released by the U.S. Army show that Buchardt gave the chief of staff of Army intelligence an exhaustive 300-page analysis of where the invading Nazis went wrong in refusing to collaborate with anti-communists in the Baltic countries and Byelorussia and White Ruthenia in the western region of the Soviet Union.

Other documents on file at the National Archives and at the British Foreign Office show that Six gave the U.S. and British intelligence services the fruits of research he had done on the Kremlin and the identity of key Communist leaders he had been ordered to seize if the Nazis entered Moscow as they expected to do in 1942. The charge to Six from Gestapo Chief Henrich Himmler is documented in a British history of World War II by E.K. Cookridge.

"At the very least, Buchardt and Six served the U.S. as Cold War advisers," said John Loftus, a one-time Justice Department attorney now writing a book on the subject who has done research on the role of the State Department's Office of Policy Coordination in recruiting anti-communist Nazis at the end of the war. "Both men were very certainly interviewed and interrogated at length by State and Army intelligence after the war."

Buchardt and Six have curious backgrounds, as did so many of the Einsatzgruppen who were put on trial at Nuremberg. Altogether, 24 Einsatzgruppen leaders were accused at Nuremberg of supervising the systematic murder of almost 2 million people in Poland and the Soviet Union. One prosecutor called what the Einsatz did the "biggest mass murder in history."

Only one of the 24 was a policeman. The rest were educated at the best universities in Germany and were described by one Nuremberg prosecutor as a "collection of Jekyll and Hydes."

By profession they included an architect, a high school teacher, a Lutheran minister, a dentist and an opera singer. Two were economists, seven were lawyers and one was a judge. Buchardt was a professor of Slavic history and Six a professor of political science at the University of Konigsberg.

"So many of these men had split personalities," a Nuremberg prosecutor said once. "On the surface, not one was a killer."

Clearly, Buchardt and Six had special expertise of interest to Army and State Department intelligence in 1950, the year the Korean War began and the Cold War with the Soviet Union worsened.

Born in Latvia and sent into the Baltic countries as an Ensatz officer right behind the invading Wehrmacht, Buchardt had close-up knowledge of the anti-communist movements in Latvia, Estonia, Lithuania and White Ruthenia. Six had his knowledge of the Kremlin; Himmler had ordered him to hunt down the Kremlin leaders and personally promoted him for his work in the Einsatz.

German Nazis were not the only Nazis recruited by the United States to work against the Soviets after the war. Loftus will charge in his upcoming book "The Belaris Secret" that the State Department's Office of Policy Coordination recruited 4,000 Byelorussians who collaborated with the Nazis and were members of self-defense militias formed to assist the Einsatzgruppen in rounding up and killing Jews in the cities of Minsk, Smolensk and Witebsk.

Recently, the FBI confirmed to The Washington Post that as many as 4,000 Byelorussian members of Nazi militia groups were allowed to immigrate to the United States even though the organizations to which they belonged were banned from sending members here by the Displaced Persons Commission. Though many thousands of innocent Byelorussians immigrated legally to the United States, others who were not so innocent immigrated here illegally.

Many of the illegal Byelorussian immigrants worked for Radio Liberty, Radio Free Europe, the Voice of America and the Defense Language Institute. A typical emigre of Nazi background was Gustaus Gelminsch, the one-time deputy director of the Swastika League in Latvia during the Nazi occupation who wound up in 1950 teaching Russian at an Air Force-sponsored program at Syracuse University until his anti-Jewish activities forced him to emigrate to Mexico in 1954. Gelminsch's Nazi past is revealed in documents turned over recently by the CIA to the National Archives.

Some German Nazis ended up as instructors at the Army's Intelligence School at Fort Holabird, outside Baltimore. The school has since been moved to Fort Huachuca in Arizona. Throughout the Korean War, three separate sources told The Washington Post, as many as 30 Germans served as intelligence instructors at Fort Holabird.

"I was there from October of 1951 through March of 1952 and there were at least 20 German instructors at the school in that time alone," one source said. "We figured they were all Nazis but it was no big deal at the time. We needed help and we didn't care where it came from."

Another source who was an Air Force pilot flying covert missions for the State Department and the fledgling CIA in the 1950s said he picked up hundreds of German- and Russian-speaking men at Weisbaden Air Force Base in West Germany and then flew them to Hanscomb Field in Massachusetts outside Fort Devens, which was then being phased out of existence.

He said the planes he flew them in had their windows painted black because U.S. intelligence officers feared some of the men were double agents already recruited by their Soviet counterparts.