According to Variety, the picture was produced by Warner Bros. at Twickenham Studios in England but was distributed in the United States by an independent distributor. This "quota" picture was called The Sleeping Cardinal in England. Copyright files reveal that the lab work was done by George Humphries and Co., Ltd. A modern source credits H. Fowler Mear with work on the screenplay. For information on other films featuring "Sherlock Holmes," consult the Series Index and see the entries above for the 1939 The Hound of the Baskervilles and Sherlock Holmes.