Harry Truman actually said...
The Secretary of State, the Secretary of War, the Attorney General, and the Secretary of the Navy are authorized to provide appropriate assistance to the member herein designated in the performance of his duties and may assign or detail such personnel under their respective jurisdictions, including members of the armed forces, as may be requested for the purpose.
Context
Executive Order 9852—Appointment of a Member of a Military Tribunal Established for the Trial and Punishment of Major War Criminals
05/14/1947