I have been studying the elements of writing a mystery novel with a small group of fellow writers, and one of the critical elements is the crime scene: why the villain killed (kidnapped, or whatever) the victim, their relationship, how it was planned, the location (including time of day, season, etc.) and exact mechanism of the crime–leading to clues. This scene may never end up in the book–in fact, it likely won’t–but the author needs to know it to the minutest detail.
I have decided that my next novel will be structured as a mystery, so this week, I constructed the crime scene. Man, I learned a lot.