Counterintelligence: J. Robert Oppenheimer

J. Robert Oppenheimer was an  American theoretical physicist and science administrator, noted as director of the Los Alamos Laboratory (1943–45) during development of the atomic bomb and as director of the Institute for Advanced Study, Princeton (1947–66). Accusations of disloyalty led to a government hearing that resulted in the loss of his security clearance and of his position as adviser to the highest echelons of the U.S. government.

(From: Encyclopædia Britannica Online)