Edward G. Robinson as Professor Richard Wanley

Joan Bennett as Alice Reed

Raymond Massey as Dist. Attorney Frank Lalor

Edmund Breon as Dr. Michael Barkstane

Dan Duryea as Heidt / Tim, the Doorman

Thomas E. Jackson as Inspector Jackson

Dorothy Peterson as Mrs. Wanley

George McFarland as Boy Scout who finds Mazard's Body

Robert Blake as Dickie Wanley

Arthur Loft as Claude Mazard / Frank Howard / Charlie the Hatcheck Man

Frank Dawson as Collins, the Steward

Frances Morris as Stenographer (uncredited)

Iris Adrian as Streetwalker (uncredited)

Brandon Beach as Man at Club (uncredited)

Paul Bradley as Man at Club (uncredited)

James Carlisle as Man at Club (uncredited)

Fred Hueston as Man at Club (uncredited)

Sheldon Jett as Man at Club (uncredited)

Jack W. Johnston as Man at Club (uncredited)

Charles Meakin as Man at Club (uncredited)

Harold Minjir as Man at Club (uncredited)

Wedgwood Nowell as Man at Club (uncredited)

Louis Payne as Man at Club (uncredited)

Scott Seaton as Man at Club (uncredited)

Wyndham Standing as Man at Club (uncredited)

Larry Steers as Man at Club (uncredited)

Don Brodie as Onlooker at Gallery (uncredited)

Frank Melton as Onlooker at Gallery (uncredited)

Claire Carleton as Blonde (uncredited)

Eddy Chandler as Police Driver (uncredited)

Tom Dillon as Police Officer Dillon (uncredited)

Freddie Chapman as Boy with Mother (uncredited)

Alec Craig as Garage Man (uncredited)

Hal Craig as News Vendor (uncredited)

Joe Devlin as Toll Collector on Henry Hudson Parkway (uncredited)

Ralph Dunn as Traffic Cop (uncredited)

Bess Flowers as Bar Patron (uncredited)

Jack Gardner as Fred, the District Attorney's Chauffeur (uncredited)

Jack Gargan as Club Steward (uncredited)

James Harrison as Club Steward (uncredited)

Fred Graham as Motorcycle Cop (uncredited)

Tom Hanlon as Radio Announcer (uncredited)

Harry Hayden as Pharmacist (uncredited)

Donald Kerr as First Elevator Operator (uncredited)

Frank McLure as Elevator Operator (uncredited)

Frank Mills as Charlie the Garage Helper (uncredited)

Anne O'Neal as Mother by Elevator (uncredited)

Dave Pepper as Club Member (uncredited)

Fred Rapport as Club Manager (uncredited)

Alexander Pollard as William the Headwaiter (uncredited)

Arthur Space as Captain Kennedy (uncredited)

Anne Loos as Stenographer