Voice of the Whistler - 5.6★

Richard Dix - John Sinclair / John Carter

Lynn Merrick - Joan Martin Sinclair

Rhys Williams - Ernie Sparrow

James Cardwell - Fred (Doc) Graham

Tom Kennedy - Ferdinand / Hammerlock

Sam Ash - Gibson Motor Car Co. Executive (uncredited)

Egon Brecher - Dr. Rose (replaced by Frank Reicher) (uncredited)

Charles Coleman - Sinclair's Butler (uncredited)

Byron Foulger - Georgie (uncredited)

Martín Garralaga - Tony, Fruit Peddler (uncredited)

John Hamilton - Doctor (uncredited)

Stuart Holmes - Sinclair Executive (uncredited)

Wilbur Mack - Sinclair Executive (uncredited)

Harold Miller - Sinclair Executive (uncredited)

Forbes Murray - Sinclair Executive (uncredited)