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. On August 3, 1948, David Whittaker Chambers, a former Communist, testified before HUAC. He charged that during the 1930s, Alger Hiss, a former member of the State Department, had been a member of a Communist cell.
National Archives, Records of the U.S. House of Representatives Used with the permission of the U.S. House of Representatives