The CIA employed former Nazi scientists to develop new interrogation techniques involving the use of LSD, a book has revealed.

According to book by us journalist Annie Jacobsen published this week, in the first years of the Cold War, Nazi doctors hired by the US, carried out tests to use Lysergic acid diethylamide, or LSD, as a mean to extort confessions from soviet spies at a safe house in the American zone of occupied Germany called Camp King.

"The facility's chief medical doctor was Operation Paperclip's Dr Walter Schreiber, the former Surgeon General of the Third Reich," Jacobsen wrote in an excerpt published by The Daily Beast.

"When Dr Schreiber was secretly brought to America—to work for the U.S. Air Force in Texas—his position was filled with another Paperclip asset, Dr Kurt Blome, the former Deputy Surgeon General of the Third Reich and the man in charge of the Nazi's program to weaponize bubonic plague."

Experiments at Camp King, which was located in the village of Oberurse, near Frankfurt, were part of a CIA operation codenamed Operation Bluebird.

"For more than a decade Camp King would function as a Cold War black site long before black sites were known as such—an ideal facility to develop enhanced interrogation techniques in part because it was 'off-site' but mainly because of its access to Soviet prisoners," Jacobsen wrote in the book titled: Operation Paperclip: The Secret Intelligence Program that Brought Nazi Scientists to America.

Bluebird stemed from a larger operation codename Paperclip, under which hundreds of German doctors, chemist and weapon makers who used to work for Adolf Hitler's Third Reich were brought to the US under secret military contracts.

The book quotes extracts from official documents, including a memorandum, written for then CIA Director Dulles which described the questioning of two agents and "suspected of working for Soviet Intelligence" at Camp King.

"In the first case, light dosages of drugs coupled with hypnosis were used to induce a complete hypnotic trance," the memo published in the book read.

"We felt that it was our responsibility not to lag behind the Russians or the Chinese in this field, and the only way to find out what the risks were was to test things such as LSD and other drugs that could be used to control human behaviour," Richard Helms, the future director of the CIA, told journalist David Frost in 1978.