The former head of German intelligence for the Eastern Front, Reinhard Gehlen, approached US intelligence, in which the CIA did not yet exist. Gehlen offered to continue his operations against the Soviet Union. Gehlen, who had played a minor part in the 20 July Plot to kill Hitler, was not considered a political Nazi. In 1945-6, he went to work with US and allied organizations, forming the Gehlen Organisation to penetrate the Iron Curtain. In this way, KGB agents that had penetrated the German spy services entered into US service. Gehlen also informed the US of certain Office of Strategic Services personnel who worked for the USSR. The CIA recruited Nazi scientists, many of whom were war criminals to work on the US Army /CIA MKULTRA Operation based at Fort Detrick, Maryland. .[1] [2]