This film shows the tedious process in 1965 of what was required in tracing a telephone call on actual central office equipment that was state of the art such as number 5 cross bar and step-by-step electro/mechanical equipment. It was filmed in central offices of the old Northwest Bell Telephone company which as of 2010 is now Century Link. Modern telephone switching equipment can trace a call in less than a minute or even 30 seconds.
Although top-billed, Sidney Poitier and Anne Bancroft don't appear on-screen together in a single scene. Bancroft later repeated this odd accomplishment when she and Sir Anthony Hopkins co-starred, but played no scenes together, in 84 Charing Cross Road (1987).
The device that Seattle PD Sgt. Ward uses to request information on the Dyson vehicle is called a telautograph machine .
Sydney Pollack's feature film directorial debut. Pollack had worked for years in television before getting his break with this film.
"Do you think that not getting caught in a lie is the same as telling the truth?" This exact quote was also used in Pollack's film "Three Days of the Condor." Another similarity between the two films is its cool shots of early telephone companies tracing calls (which is not an easy task).