Witness to Murder is about a woman (Barbara Stanwyck) who looks out her window one night and sees in the facing apartment what she thinks is a murder. She contacts the police who investigate but find no evidence and so are skeptical. The woman decides to gather evidence on her own. Her activities quickly bring her to the attention of the murderer (George Sanders), who takes steps to shut her up. The film was released, as was RW, in 1954. Coincidence? The short answer is yes.
Now for the longer answer: both WtM and RW share a common antecedent. In The Window (1949), a boy can’t convince his parents—let alone the police—that he has witnessed a murder. Even earlier, Sorry, Wrong Number (1948), another Stanwyck picture, featured a woman in danger who has discovered a murder plot and whom no one believes. Another influence on WtM—if not RW—is probably Gaslight (1944), as part of Saunders’ strategy to avoid detection is to discredit Stanwyck by making her appear a mental case. He does his job so well he has even Stanwyck’s character questioning her sanity.
It’s interesting to compare and contrast WtM and RW. In WtM, Stanwyck’s character uses binoculars to study the murderer in his apartment across the way. Also, Saunders makes a late attempt on Stanwyck’s life. He visits her in her room and tries to throw her out her window, the very one through which she witnessed the initial crime. The film differs from RW in a number of ways, most notably in that there is never any doubt about the crime. Also, the film spends a lot of time with the murderer; long before we’re introduced to Stanwyck we see Saunders acting to avoid detection.
WtM is an entertaining film, with good performances, moments of suspense, and high-contrast B&W photography by John Alton (it was directed by Roy Rowland). But it doesn’t have Grace Kelly, the exploration of a mammoth single set, the witty dialog of John Michael Hayes, or Hitchcock’s deft direction. WtM is what you might expect Hollywood to produce after rolling out any number of woman-in-peril pictures. RW remains sui generis.