I guess the plan for murder is considered somewhat novel and unexpected. That may be, on paper, but in reality it is extremely stupid. The whole case could be solved within the first 5 minutes of discovering the deceased had been answering a call because, whoever the killer is (and there must be one as the sleuth explained), he is aware that someone is at home at this particular time. And as the victim is only there at the behest of the Williamson character (also established), only the latter could be the murderer.
Thus, the smoke-screen of clues and suspense were just there for their own sake, entirely useless to the plot. The whole business about referencing Citizen Kane serves no practical purpose (other than giving a niche impression), and having the murderer accidentally slipping out "Rosebud" just seems a bit ... desperate for the writers. Altogether, not an example of effective use of screen time, and the best scene for me is the one where Columbo scorned the murderer for incompetence and stupidity ... raised a lot of empathy in me.
Thus, the smoke-screen of clues and suspense were just there for their own sake, entirely useless to the plot. The whole business about referencing Citizen Kane serves no practical purpose (other than giving a niche impression), and having the murderer accidentally slipping out "Rosebud" just seems a bit ... desperate for the writers. Altogether, not an example of effective use of screen time, and the best scene for me is the one where Columbo scorned the murderer for incompetence and stupidity ... raised a lot of empathy in me.