Formed in May 1938 the House Un-American Activities Committee (HUAC) investigated disloyalty among American citizens. It became extremely powerful during the Cold War years and focused its investigations on left-wing political activities, especially on individuals accused of Communist sympathies. David Whittaker Chambers delivered classified documents he said had been given to him by accused spy for the Soviet Union Alger Hiss. Because Chambers hid this evidence in pumpkins, the documents became known as the Pumpkin Papers.
National Archives, General Records of the Department of Justice