Have you ever read the Hitchhiker's Guide to the Galaxy books? There's a minor almost-protagonist in one of the later ones who works as a truck driver, and everywhere he goes, rain follows. Turns out - and this isn't much of a spoiler - he's a bona fide rain god, and rain, sentient as it isn't, loves to be near him, wherever he goes.
Now, murder may be an even more intangible concept than rain, and we could argue all day whether a murder has a mind of its own outside of the perpetrator, but let me tell you this: Jessica Fletcher is an unwitting murder god. Like the truck driver, murder wants to be near her, no matter what. It wants to be soothed by her solving, and to be written about.
"Why do people keep inviting her to different places?", you might ask. They're as unwitting as she is, and murder somehow manages to dull their senses when it comes to its actions. I mean: It's murder. It's not exactly a pleasant, charming thing like the rain can be.
At least the truck driver was allowed a level of self-awareness towards the end of his protagonism. Jess Fletcher wouldn't have got that until Death himself decided to call time on it.