Suburb of Heaven

I've read Dibden and Pears and Leon too, but for an interesting other point of view, I've enjoyed genuine Italian police procedurals, by which I mean Italian novels by Italians. I think those are very useful for getting a sense of what Italians think about their government's corruption (or lack thereof), and in avoiding the stereotypes that foreigners may inadvertently use. I'm fond of the novels of Andrea Camilleri, which involve a Sicilian police officer and are set in Sicily. They're wildly popular in Italy, so even if they're not realistic about how the Italian police work, they're a good picture of how Italians like to imagine their police as being. They've been translated into English recently, so they're available in the US.