One of the first films to be shot in the Los Angeles River.
Completed after L'énigme du Chicago Express (1952), one of Charles McGraw's other notable film noir starring roles, but released before that film because RKO Pictures owner Howard Hughes toyed with the idea of reshooting all of McGraw's scenes with Robert Mitchum in that film in order to boost it's profile. That film was ultimately released as originally shot the year after this one.
Joe's car is a 1950 Plymouth De Luxe 4-door sedan.
Some of Paul Sawtell's score was simply recycled from Dick Tracy contre Cueball (1946) and subsequent films in the Dick Tracy series that RKO released in the late 1940s.
The airplane Joe and Diane are depicted as boarding in Cincinnati is a TWA Douglas DC-3-209, serial no. 1967, registration NC17321, TWA fleet no. 371, built in 1937. It flew with TWA until January 1953. In 1974 it was sold to Trans Oriental Airlines in Bolivia, fate afterwards is unknown.