The nice thing about your police procedural as opposed to your classic murder mystery is that in a murder mystery you don't know who did it. Whereas in a police procedural you know, you know everything often and you're watching the police home in.
Terry PratchettCheery was aware that Commander Vimes didn't like the phrase 'The innocent have nothing to fear', believing the innocent had everything to fear, mostly from the guilty but in the longer term even more from those who say things like 'The innocent have nothing to fear'.
Terry PratchettAnd then Jack chopped down what was the world's last beanstalk, adding murder and ecological terrorism to the theft, enticement, and trespass charges already mentioned, and all the giant's children didn't have a daddy anymore. But he got away with it and lived happily ever after, without so much as a guilty twinge about what he had done...which proves that you can be excused for just about anything if you are a hero, because no one asks inconvenient questions.
Terry Pratchett