A scene from “Unfinished Business”

Ian O'Connor: [after Jessica exposes the murderer] I don't believe it. That doesn't make any sense.

Jessica Fletcher: I'm afraid it makes perfect sense. Michael O'Connor blamed Sean for all of his problems, and hated him for taking the woman that he loved. When Michael left Ireland, he was in such a hurry that he sold his property for a fraction of its value. Something extraordinary must have happened to make him cash in everything and leave like that.

Lt. Parnell: It's as if he knew he wouldn't be coming back. It's the kind of thing you do when you know you're gonna die. Close everything out, put your affairs in order, make sure the money goes to your next of kin.

Jessica Fletcher: Which hardly fits the picture of a man who never thought ahead.

Ian O'Connor: But why? Why would he do all this?

Jessica Fletcher: Because he was already dying, Ian. This evening, I spoke to his doctor in Ireland. A few months ago, Michael was diagnosed with an inoperable brain tumor and given six months to live. I noticed when he spoke, he sometimes stammered, and he repeated his words at unnatural intervals, both indicators of a possible tumor. It must have come as a double blow to know his own life was ending just as Sean was beginning a new life in the United States.

Lt. Parnell: So, he decided a quick death was preferable over a slow and painful one.

Jessica Fletcher: And why not take Sean with him? It would be his final revenge. To frame Sean for his own death. Michael went out of his way to provoke Sean into threatening him to start a paper trail with the police. Taunted him so that Sean would get his fingerprints on the card you would later find beside the body, establishing his presence. He was carefully building a body of circumstantial evidence, knowing that the word of a dead man is admissible in court. And, of course, the videotape was the final touch.

Lt. Parnell: What about the gun?

Jessica Fletcher: Well, that was the ingenious part. But it was also the part that betrayed him. He cut into a high wall, ostensibly for a window, but mainly to get access to the hollow space within the wall. He then slipped a heavy steel weight into the gap and attached the other end of the long rope to the gun, knowing that as soon as he released the gun, it would be yanked up into the wall. But when he released the gun, it was pulled back with enough force to cause this scrape and the rope itself to cut into the wall at the edge of the opening.

Lt. Parnell: "To the last will I grapple with thee."

Ian O'Connor: What's that?

Jessica Fletcher: Melville. Captain Ahab lashing out at the great whale even as he died. "For hate's sake, I spit my last breath at thee." Yes. Obsession has always extracted a terrible price, Lieutenant. A terrible price indeed.