Sherlock Holmes in Washington 1943 is the fifth film in the Basil RathboneNigel Bruce series of Sherlock Holmes movies. The plot is an original story not based on any of Sir Arthur Conan Doyles Holmes tales, though it bears some similarity to The BrucePartington Plans.
John Archer and Marjorie Lord, who play an engaged couple in this film, were a married couple when it was made. The two main villains in Sherlock Holmes in Washington played Holmes nemesis Professor Moriarty in other films. George Zucco played the role in The Adventures of Sherlock Holmes 1939, and Henry Daniell portrayed Moriarty in The Woman in Green 1945. Gerald Hamer, who appeared in four other of Rathbones Holmes movies, has a brief, uncredited but pivotal role in this one.Oscar Homolka was originally cast in this film as Holmess elder brother Mycroft. He quit the part due to family issues, and Mycrofts character was replaced by Mr. Ahrens, portrayed by Holmes Herbert. ........
Source: Wikipedia