Structure – otherwise known as Can of Worms.
The Mirror Structure
For example, you could start with either a first person or third person short prologue about why the unnamed and, if you can, un-gendered, narrator —usually the perpetrator — rationalises what he or she did. It is a kind of In my end is my beginning type of book and if you can pull it off, it will be spectacular.
The Milieu Structure
The Idea and Character Story
This is where the idea starts the ball rolling. Who gets killed, who killed him/her and how the killer is caught. The character story is exploring how your main character grows – or doesn’t – through the action of finding the killer. And please, I beg of you, no washed up cops, who drink too much and have inner demons. My own opinion is that if you want to read of such characters and how they cope — or don’t — read literary fiction. A crime story is about crime. It involves characters and how they see the world and yes, you probably need to allow the reader into a bit of their private lives, but would you take all your angst and demons to work with you? Do you think if you did you would be in that job very long?