Published in Detective Comics #47, January, 1941, 6 pages.
Receiving a call from a scared man claiming to have information 'vital to this country's defense', the Chief has the call traced (but the man does give his address) and sends Bart Regan to investigate. Regan is told by that man that he is the only person outside an organization of agents from a 'great foreign power' that knows the location of a new radio station set up in Central America to 'pump their filthy propaganda into the U.S'. Regan smells a rat.