Published in Detective Comics #26, April, 1939, 6 pages.
The US "Congress building" is destroyed by a terrific explosion. The Chief informs Bart Regan and Sally Norris an hour later that the reports in the newspapers about it being due to faulty gas pipes were incorrect (timing on all that is very odd). The pair are told to discover what really happened. That leads them to suspect it was bombs directed by radio-control. That leads them to a scientist who has created a sky-torpedo. Norris will be taken for one heckuva ride!