
Several murders of nuclear scientists, that baffles Scotland Yard, occur in London around the same time that Bill Locklin, a special officer from the United States State Department, arrives to oversee the transfer of Professor Leon Dushenko, a Russian scientist who has fled the USSR. An attempt on Dushenko's life is made with a monkey's paw-print found at the scene.

Richard Conte
Bill Locklin

Rona Anderson
Julia Jackson

Russell Napier
Supt. John Harrington
Sylva Langová
Hilde Heller, chief spy

Colin Gordon
Harry Martin - reporter

Donald Bisset
Editor Harris
John King-Kelly
Spy Henchman
Bernard Rebel
Vinson - Spy Henchman

Arnold Marlé
Prof. Leon Dushenko

John Horsley
Det. Sgt. Gibson

Jane Welsh
Supt. McCollum - sanitarium

Aimée Delamain
Mrs. Henley

Sherlock Holmes
Sherlock Holmes

My Friend Violet
My Friend Violet

The Blue Parrot
The Blue Parrot

Brannigan
Brannigan

The Woman in White
The Woman in White

Saab Bahadar
Saab Bahadar

Green for Danger
Green for Danger

Villain
Villain

Lured
Lured

Rollin' with the Nines
Rollin' with the Nines

The Gunman
The Gunman

9 Dead Gay Guys
9 Dead Gay Guys