There is a fine line between being subtle and cheating, when it comes to who actually committed the crime in a mystery. You don't want to be too obvious, because it takes the fun away, but the reader has to at least have a chance to see it coming. Otherwise they are going to be (rightfully) salty when the culprit comes out of nowhere and there were no clues.
So today that's what we're going to talk about.
Part of the generally accepted mystery formula is 'the return to an overlooked clue from act one' that makes things pretty clear. The key word here is 'overlooked'.
A few of your clues should be ambiguous but at least a couple of them should be damning for another suspect entirely. That unsatisfactory conclusion to the mystery is pretty great because it shows that your sleuth is capable of making mistakes in a very human and relate-able way, and it's a good way to obfuscate the real bad guy for at least a little longer.
You know why the trope is that the butler always did it? Because in the classic 'everyone is stuck in the mansion until the killer is found' story format, the butler is someone who is around but basically just an expected part of the backdrop. You don't really think of him as being a character. Not with all these other rich peacocks around.
The easiest way to do this is to set someone up who is present in the story but not likely to be a suspect. Someone overlooked. A bartender. The person who reported the crime in the first place (possibly to make themselves look less guilty). Someone with access to the victim and the means to do it, but someone who isn't as obvious a prospect as the other parties nearby.
Then, as you're describing the scene of the crime, slip in a few subtle clues that point to this person.
Make sure you tie the clue to them somehow, but do it in a subtle way. Under no circumstances is your sleuth allowed to go "Oh, it looks like this wound was made by a heavy blunt object like one of the trophies in Butch's trophy case", if Butch actually bludgeoned them with the trophy.
Make it a point to contrast the grizzly scene with the awards in the outer hallway. Have Butch answer the door with the trophy in his hand and make a comment about how cleaning gets him out of his own head. Wait a couple of pages (after some much more flashy descriptions of the body, of the house, after other information and potential suspects come up) and then describe the smell of dust in that room on the way out again.
Give the detective too much to think about at first, so that later whey're looking into the refrigerator they can stand up straight and go "By jove! That wasn't right!"
Oh yes, this definitely involves knowing who did it from the very beginning. And you do have to keep that person present in the story so the reader doesn't forget about them because otherwise you're cheating. And that sounds like a lot to keep up; that's because it is. But it gets easier.
Anyway, let me take a moment for my shameless plug; Demons. 1920's. Mob activities (haha it sounds like they're coloring with crayons, doesn't it? They are not coloring with crayons, more like the brains of their enemies). These are some of the fun things you can expect from my latest novel. Torchlighters, coming out in February 2019. Keep checking back here, on my blog, for the pre-order link.
Megan R. Miller