People sometimes ask when I am going to write a serious one, meaning a bloody one. The question assumes that gentleness and rigor cannot share a book. They can, and putting them together is harder than leaving one of them out.
The contract
A cozy makes the reader a few promises. The violence stays off the page. The dead are treated with decency, not opened up for entertainment. And the town matters as much as the crime, so that when the book ends the place is still standing and the people in it still have to live together. Those are real constraints, and I keep them not because I am squeamish but because they are the terms of the kind of book I set out to write.
Not the same as soft
The puzzle is no softer for any of that. The mechanism still has to be sound, the clues still have to be fair, the solution still has to be the only one the evidence allows. If anything the decency tightens the screws. I cannot solve a plot problem with a chase or a gun or a confession beaten out of somebody. The pressure in the book has to come from what people know and will not say, and from what the evidence costs once it is out. Take away the loud tools, and what is left is the hard work.
Why a small town
I set these books in a small town because a small town has memory. Everyone is known. Every person has a history on the same few streets, a reputation, and someone who remembers the last time. An act in a town this size has witnesses, and its costs land on people who will still be there next year. That standing history is what makes consequence possible at all.
Anonymity is the enemy of consequence, and a city is full of it. In a crowd a person can do a thing and vanish, and no one is left who has to carry what it did. A small town gives no one that exit, which is exactly why it is good ground for this kind of story.
What the lab left me
My own reason is plainer than any of that, and it comes from the years before I wrote a word of fiction. I spent a working life close to real consequences, the kind measured in shut-down lines and, once in a while, in people who did not go home. I learned in that work that I do not find pain entertaining, and I have not changed my mind about it since.
A puzzle is a different matter. Taking a hard problem apart until it makes sense is one of the few pleasures that has never worn out for me, and it does no harm to anyone. The cozy is where those two facts can both be true. The problem is real, and the pain is not the show.
The safety of the form does not soften what the reader is owed. Inside it, the reader still gets a real surprise, one that was fairly built and could have been seen coming. Comfort is not the same as a soft touch. The rooms are warm and the rules are strict, and I would not write the other kind.