Iron Lake by William Kent Krueger

Part Irish, part Anishinaabe Indian, Corcoran “Cork” O’Connor is the former sheriff of Aurora, Minnesota. Embittered over losing his job as a cop and over the marital meltdown that has separated him from his wife and children, Cork gets by on heavy doses of caffeine, nicotine, and guilt. When a powerful local politician is brutally murdered the same night a young Indian boy goes missing, Cork takes on a harrowing case of corruption, conspiracy, and scandal.