Robicheaux by James Lee Burke

Robicheaux is the latest in the excellent (albeit generally violent) series featuring Louisiana cop Dave Robicheaux and his best friend Clete. As the story begins, Dave is still dealing with the death of his wife Molly in a car accident. When the driver who hit her ends up dead, Dave becomes the main suspect. And because he was very drunk at the time, he's not completely sure he didn't kill the guy. The cop assigned to investigate is a shady transplant from Miami called Spade Labiche, who may have ties to a local mobster. At the same time, a mysterious hitman called Smiley has arrived in town and is causing maximum damage. And Clete is trying to hang onto a young boy he has rescued from an abusive home and for whom he is serving as unofficial guardian. As usual, there are several other subplots going on and several beautifully descriptive passages on the Louisiana countryside, weather, and history.