I’ve just been listening to Georgette Heyer’s ‘The Quiet Gentleman’. Heyer as usual provides an excellent example of how to do something really very difficult with such skill that the reader (listener) does not realize the the author is playing them.
Now… spoilers follow. But the core of the story involves misdirection in what amounts to murder mystery (in Regency Romance clothes). We’re all used – in real life- to villain who masquerades as a good guy — we’ve all encountered politicians, who claims to be motivated by a desire to help you (as governments always claim to wish to). So: you’d think we’d be inoculated against it.
However… we keep electing them and they keep claiming they’re there to help, despite turning things from mildly awkward to deadly chaos, from which they somehow reap power and money every single time. So, you might say humans were designed to be gullible (or enough humans) and a subsection of the population is really good doing it.
Writing it well, however, is a different matter. We’re used – as writers, to tagging our heroes and villain clearly so the reader can sympathize and empathize with the good guy or desire to see the comeuppance of the bad. That’s a bit tricky where the core purpose of the story is to NOT reveal the actual villain (and occasionally the actual hero) until the reader has been able to have a fair go at working it out for themselves. Ideally they don’t get it until the denouement, despite all the clues being there, and it is obvious AFTER the denouement.
The lazy writer’s technique for for dealing with this is to have a lot of characters with motive and so unpleasant that the reader thinks any one of them could have done it, and are happy for any of them to get led off to face the consequences. The inevitable red-herrings are just yet another nasty character, that even if they didn’t do it, the reader was happy to suspect.
The downside is a book full of nasty characters, except for the detective, is a rather like swimming through a sewer. It might get you somewhere, but it stinks.
The opposite extreme is of course where all the characters appear nice, and it’s only detective work that reveals so-and-so is the villain. The problem is that your readers end up sympathizing with the villain – especially as red herrings are probably less nice.
Then there is, as in the book that I was listening to, the villain hidden in plain sight, and the herring (or planned scapegoat in this case) starting unpopular, but the author slowly redeems them. The villain… spends a lot of time pointing out the scapegoat’s motive. The author very carefully into each scene, but colorlessly inserts the facts that villain has the same motives – and more. The author cheerfully tells us that the character came from shaky beginnings – but his behavior is the inverse of his parentage and youthful rearing. The villain… seems a good guy, who worries about (potential) victim. The scapegoat seems a jackass. Gradually small redeeming points are introduced. Gradually small negatives are added to the actual villain. And gradually we’re brought to see them as less attractive as a character – by the way they treat other characters – not the (potential) victim.
However the hand of the author – using the villain to plant suspicions in the reader’s mind – by means of making the like-able secondary characters suspect the scapegoat – at the instigation of the villain, to some extent, is what drives the plot. Heyer openly tells you that the villain has worked hard for no reward for an estate that he will never own – unless the hero and scapegoat both die, that he desires the girl he uses as the scapegoat’s motive, and that he has developed a passion for a place that can never be his… unless of course the hero and scapegoat die. The later is never spelled out, but the scapegoat’s motives are the same (but he does have a considerable inheritance -the villain has none) – But she contrives to have the villain put the actions of scapegoat in the worst possible light.
It’s nice work, if you can do it.
Image by For commercial use, some photos need attention. from Pixabay
Mad Genius Club 
The advantage of nice characters in a murder mystery, per G. K. Chesterton, is that the revelation can *shock*, not just surprise.
I confess, the last mysteries I read were Tony Hillerman novels, and I read those a much for the place as the stories. In half the books, one of the protagonists (Jim Chee) believes in medicine power, good and evil, and that works into the plot. [Skinwalkers, for example]. That adds the element of “some characters do take this seriously, others don’t take it seriously, so how serious is it?” Hillerman managed it well, but that’s more of a police procedural than a cozy or other kind of mystery.
In my opinion, one of the cleverest character developments that Heyer did was in Cotillion – wherein a male character who initially appeared as sort of a comic, slightly-effeminate buffoon developed into an endearing and even quietly heroic leading man over the course of the book.
I want a mystery in which the first suspect is actually the guilty party. It never is. It makes that first suspect very boring to read about because you know that, however much evidence points that way, he will not be guilty.
Been done. Not a book, but a movie. “She Woke Up” 1992, Lindsay Wagner and David Dukes. There, I’ve spoiled it for you.