This was Robert Culp's fourth and final appearance in "Columbo", and the only time he did not play the murderer.
The red herring about the victim having written a book exposing mafia figures, an attempt to explain the murder, was also in Un giallo da manuale (1971) (directed by Steven Spielberg), only in that case, the (supposed) book was being worked on by the victim.
One of the few episodes where Columbo appears on-screen before the murder occurs.
In this episode, Columbo is a guest lecturer at a criminology class. He reminisces about the prior season's Agenda per omicidi (1990), describing how he obtained a piece of chewing gum belonging to murder suspect Oscar Finch (Patrick McGoohan), which was matched to teeth-marks on a piece of cheese left at the murder scene.