A "Chekhov's gun" is a dramatic principle that states that if you introduce an (ominous) element into a story, you need to use it in a subsequent scene or it has no business being there. The term comes from the playwright Anton Chekhov, who once said, ""If in Act I you have a pistol hanging on the wall, then it must fire in the last act." (Donald Rayfield, Anton Chekhov: A Life, New York: Henry Holt and Company, 1997 - thank you, Wikipedia.) In Close-up on Murder, the Chekhov's gun is literally a gun, the one that skids to a stop at Jessica's feet after Mort disarms Neil Corday. She picks it up, and then, not knowing what else to do with it, she puts it in her handbag. Since there was no mention of her turning it over to Mort between the end of that scene and the beginning of the climactic scene that took place next, I thought it was being foreshadowed that this gun would have some role to play in how the climax unfolded, as I assumed she was still carrying it when she confronted the murderer. It didn't. In fact, it was never mentioned again, and I felt somewhat let down.