We strongly suggest you save yourself some moolah and instead.
Not exactly a stretch. Murder victims are found buried with some of their wordly goods, Viking style. Some clues should point the sleuth in the right direction, others may not be obvious or be recognized as actual clues unto later in the story.
Rowling lets us into the mind of an anonymous stalker in A Career of Evil. Then you go at it again, expanding to paragraphs, or whole pages if you want to. As does her amateur sleuth, Benni Harper, now on her 12th or 13th novel in a hugely successful series. Writing a mystery means understanding this narrative formula and designing your plot around its structure.
All a writer has to do is "twist" that story a little bit - the "what-if" that inspires all storytelling - and a mystery emerges. At the same time, a mystery is often set up as a kind of puzzle or game for readers, who analyze clues and try to solve the mystery themselves.
We want the violator of the social compact - the killer, the thief, the blackmailer - caught, so that things in our world are set right once more. The three things to keep in mind when writing mysteries are: 1 establishing the unique character of the protagonist, 2 making narrative use of the world in which the story takes place, and 3 planting clues remember, only a few that derive from the particular aspects of that world.
Nobody reads a mystery to get to the middle.
The sub-plot should be introduced. Act Three ends with the discovery of the villain.