The documents are of great importance. They show in detail how both Soviet and Western Intelligence Services hired, recruited and exploited a large number of former Nazi SS officers. Many of them occupied crucial posts during the Cold War, a tremendous security risk to the Allies.
During the Second World War, Heinz Felfe was a Nazi SS officer with the SD Sicherheitsdienst, the Foreign Intelligence branch of the SS. After the war he was recruited in Münster by British Intelligence. Their cooperation ended in 1950 when he was suspected of working for the Soviets. Felfe however managed to get a job in the Counter-Intelligence section of the Gehlen Organization, the predecessor of the BND (Bundesnachrichtendienst), West German Intelligence. This agency, sponsored by the US Army and the CIA, was lead by general Reinhard Gehlen, the former head of WWII German intelligence on the Eastern Front.
Felfe’s superiors in the Gehlen Organization, many of whom had also worked during WWII for Nazi intelligence organizations, were themselves Soviet agents. This cleared the path for Felfe's advances in the hierarchy of West German Intelligence. In 1955 he became head of the counter-intelligence against the Soviets, at the same time being a Soviet agent himself. No wonder the Gehlen Organization had a disappointing record in supplying valuable intelligence on the Warsaw Pact.
A higher living standard than his wage could provide, his often expressed bitterness on the Allied destruction of Dresden, his criticism on Western democracy, clues from Soviet defectors and information, collected by the CIC (US Army Counterintelligence Corps) eventually led to his arrest by West German authorities in 1961. In 1969 he was released to East Germany in exchange for three West German spies.
Heinz Felfe caused enormous damage and embarrassment to Western Intelligence. His position enabled him to obtain information from his and many other West German offices such as the Bundesamt für Verfassungsschutz BfV (West German Federal Intelligence) and the Foreign Ministry. According to the CIA, Felfe compromised a large number of CIA agents, about 15,000 documents and sabotaged most counter-espionage, surveillance and arrest operations against Soviet agents in West Germany.
All information is found at the CIA Heinz Felfe files (pdf) link. In these documents, Felfe has the codename FRIESEN. These extraordinary CIA files are published by the FAS Project on Government Secrecy on their e-print page, which contains many more interesting documents.
Last year, the Frankfurter Allgemeine (German) published an article about the FSB - Russia's Federal Security Service - honoring Heinz Felfe at this 90th birthday (translated version here). Felfe published his full biography in 1988 in East-Germany (ISBN: 3373002737). This book, which was not for export, is more complete than the West version. Nice read. Felfe died in May last year.