Directed by
Roy William Neill

Writing credits
Arthur Conan Doyle (story) (as Sir Arthur Conan Doyle)

Frank Gruber, adaptation
Leonard Lee, screenplay

Basil Rathbone.... Sherlock Holmes
Nigel Bruce .... Dr. 'Fatso' Watson
Patricia Morison .... Mrs. Hilda Courtney, aka Mrs. Williams
Edmund Breon .... Julian 'Stinky' Emery (as Edmond Breon)
Frederick Worlock.... Colonel Cavanaugh (as Frederic Worlock)
Carl Harbord .... Inspector Hopkins of Scotland Yard
Patricia Cameron .... Evelyn Clifford
Holmes Herbert .... Ebeneezer Crabtree, auctioneer at Gaylord Art Gallery
Harry Cording .... Hamid, Cavanaugh's chauffeur
Leyland Hodgson....Tour guide
Mary Gordon ....Mrs. Hudson
Ian Wolfe .... Commissioner of Scotland Yard

Others (alphabetically)
Frank Baker .... Photographer (uncredited)
Guy Bellis.... Doctor (uncredited)
Wilson Benge .... Minister on museum tour (uncredited)
Marjorie Bennett.... Antique shop assistant (uncredited)
Ted Billings .... Pub extra (uncredited)
Lillian Bronson .... Minister's wife (uncredited)
Tom Dillon .... Detective Sergeant Thompson (uncredited)
Topsy Glyn .... The Kilgour child (uncredited)
Charlie Hall .... Cab driver (uncredited)
Olaf Hytten .... Alfred, auction house bookkeeper (uncredited)
Boyd Irwin .... Detective with x-ray photos (uncredited)
Tiny Jones ....Pub extra (uncredited)
Guy Kingsford .... Scotland Yard undercover convict (uncredited)
Wally Scott.... Joe Cisto, pub pianist (uncredited)
Anita Sharp-Bolster.... Teacher on museum tour (uncredited)
Sally Shepherd ....Tobacconist (uncredited)

Also Known As:
Prelude to Murder (USA) (working title)
Sherlock Holmes and the Secret Code (UK)
Sherlock Holmes in Dressed to Kill

info from imdb.com

Audio/Visual: sound, b&w
Keywords: Mystery; Thriller, Drama

run time: 1:11:30