The Phantom Fleet
E. Phillips Oppenheim
First published in The Strand Magazine, Sep 1934 and 2nd of 4 stories in the series General Besserley Intervenes. 4th story in the collection .
Washington comes calling in the form of an American businessman with a coded message wanting his help in a matter. The curious thing to Besserley, though, was the man bringing the message used the name of a man murdered a couple days before.