In two different scenes a cab comes to the mansion, and both times it has the same license plate.
The two climactic auto scenes were filmed at Cielo Drive and Davies Drive in Beverly Hills, California.
When Robert Mitchum got fed up with repeated re-takes in which the director Otto Preminger ordered him to slap Jean Simmons across the face, he turned around and slap Preminger, asking whether it was this way he wanted it. Preminger immediately demanded of Howard Hughes for Mitchum to be replaced. Hughes refused.