Larry and Sally screen The Phantom of the Opera (1925), which he cites as one of the films directed by the long-ago murder victim, Franklin Ferrara. Of course, the film was directed by Rupert Julian, but the writers obviously felt (no doubt correctly) that audiences in 1951 would not know or remember this, plus it allowed them to re-use footage of a silent classic.
Story is fiction but loosely based on the real-life 1922 murder of film director William Desmond Taylor, which ruined the film careers of Mabel Normand and Mary Miles Minter. The case has never been solved.
The studio that was rented in the film that had the bungalow was actually Charlie Chaplin's Studio
Silent stars Francis X. Bushman, Betty Blythe, Helen Gibson and William Farnum are featured, but Elmo Lincoln appears in an unnamed bit part. Joel McCrea who appears in one scene was also in silent films.
Rudolph Valentino is pictured in a photograph and mentioned. Silent star Beverly Bayne, who was once married to Francis X. Bushman, is also mentioned.