The AFL began pushing for an investigation into the NLRB, and this investigation led to allegations of communist influence within the agency. In June 1938, the House Un-American Activities Committee (led by Chairman Martin Dies, Jr. [D-TX]) heard testimony from AFL leader John P. Frey, who accused Madden of staffing the NLRB with communists. The allegations were true, in at least one case: Nathan Witt, the NLRB's executive secretary and the man to whom Madden had delegated most administrative functions, was a member of the Communist Party of the United States. These allegations and discoveries significantly damaged the agency's support in Congress and with the public.