In August 1938, Marshall began his last trip to Alaska, which included further exploration of the Brooks Range. He became a subject of interest of the House Un-American Activities Committee, a House of Representatives committee investigating "un-American" activities. Known as the Dies Committee for its chairman, Martin Dies, the committee announced in "The New York Times" that eight federal officials (including Marshall) were contributing to communism because of their connections to such organizations as the Workers Alliance and the American League for Peace and Democracy. Marshall was too busy traveling to respond to the allegations: after leaving Alaska he spent time in Washington state, Montana, Oregon, Nevada, Utah, Arizona, New Mexico and California. He visited Alaska for one last time the following year and made a tour of western national forests, addressing aspects of forest recreation.