Probe

Hugh O'Brian

— Hugh Lockwood

Elke Sommer

— Heideline 'Uli' Ullman

Burgess Meredith

— V.C.R. Cameron

Lilia Skala

— Frieda Ullman

Angel Tompkins

— Gloria Harding

John Gielgud

— Harold L. Streeter

Kent Smith

— Dr. Edward Laurent

Alfred Ryder

— Cheyne

Ben Wright

— Kurt van Niestat

Robert Boon

— Felix Ernst

Albert Popwell

— Dr. Griffin

A Martinez

— Carlos Lobos

Byron Chung

— Kuroda

Ginny Golden

— Miss Keach

Jules Maitland

— Reinhardt Brugge

David Ahdar

— Hotel Clerk (uncredited)

Robert Cole

— Waiter (uncredited)

John Daheim

— Guard (uncredited)

Jan Daley

— Lockwood's Girl (uncredited)

Joanna Frank

— Stewardess (uncredited)

Dale Johnson

— Waiter (uncredited)

Joe Pine

— Hotel Guest (uncredited)

Murray Pollack

— Hotel Guest (uncredited)

Ford Rainey

— Aaron Johannes (uncredited)

Tony Regan

— Waiter (uncredited)

Jeffrey Sayre

— Hotel Guest (uncredited)

Jaclyn Smith

— Stewardess (uncredited)

Judith Woodbury

— Hotel Guest (uncredited)