While the FBI Cointel program was revealed in the early 1970's, . . mostly all of the information about the CIA Experimental programs, had been destroyed by the Director of the CIA in 1973
Project MKUltra was first brought to public attention in 1975 by the Church Committee of the United States Congress and Gerald Ford's United States President's Commission on CIA activities within the United States. Investigative efforts were hampered by the fact that CIA Director Richard Helms ordered all MKUltra files to be destroyed in 1973; the Church Committee and Rockefeller Commission investigations relied on the sworn testimony of direct participants and on the relatively small number of documents that survived Helms's destruction order.