 In July 1945 , FBI director J. Edgar Hoover instructed his agents to begin gathering information on CPUSA members to support an analysis of the Party 's subversive goals , leading to a 1 @,@ 850 @-@ page report published in 1946 which outlined a case for prosecution . As the Cold War continued to intensify in 1947 , Congress held a hearing at which the Hollywood Ten refused to testify about alleged involvement with the CPUSA , leading to their convictions for contempt of Congress in early 1948 . The same year , Hoover instructed the Department of Justice to bring charges against the CPUSA leaders with the intention of rendering the Party ineffective . John McGohey , a federal prosecutor from the Southern District of New York , was given the lead role in prosecuting the case and charged twelve leaders of the CPUSA with violations of the Smith Act . The specific charges against the defendants were first , that they conspired to overthrow the US government by violent means , and second , that they belonged to an organization that advocated the violent overthrow of the government . The indictment , issued on June 29 , 1948 , asserted that the CPUSA had been in violation of the Smith Act since July 1945 . The twelve defendants , arrested in late July , were all members of the National Board of the CPUSA : 
