Frank Olson had joined the Special Operations Division of the Army's Biological Laboratory at Fort Detrick at its inception in 1950. He was issued a Q clearance, the civilian equivalent of the military's top secret clearance, and worked with the CIA on MK-ULTRA.As part of that work, he traveled in 1953 to Britain, France and West Germany. At the secret British military research center at Porton Down, the sons say, Olson witnessed "extreme interrogations" in which "the CIA committed murder" using biological agents Olson had developed.They say a psychiatrist there, William Sargent, grew concerned that Olson "had serious misgivings related to those murders and might therefore pose a security risk," and so recommended to his superiors that Olson no longer be granted access to classified research facilities in Britain.source: Six decades later, sons seek answers on death of Detrick scientistThe Baltimore Sun, 8 December 2012