Produced by Universal for NBC, the same entities that pioneered the made-for-television movie (with See How They Run (1964), the first full-length film produced especially for television), this movie was the first television movie produced as a pilot that was picked up for a regular series (becoming The Name of the Game (1968)).
Tiffany Thayer's novel had been published in 1933, and was the basis of an Alan Ladd film of 1949, "Chicago Deadline". The plot was clearly inspired by the case of "Starr Faithfull" (not her real name), a "model" who was fished out of the East River in New York in the 1920s and presumed to have committed suicide. After the discovery of an address-book with a lot of famous names in it, whispers went around that she was actually a call-girl who had been blackmailing some of her high-profile clients, and that she had actually been murdered. Nothing was ever proved, however.