Black mountain - Laird Barron

When a small-time criminal named Harold Lee turns up in the Ashokan reservoir - sans heartbeat, head, or hands - the local Mafia capo hires Isaiah Coleridge to look into the matter. As Coleridge turns over more stones, he finds himself dragged into something deeper and more insidious than he could have imagined, in a labyrinthine case spanning decades. At the centre are an heiress moonlighting as a cabaret dancer, a powerful corporation with high-placed connections, and a serial killer who may have been honing his skills since the Vietnam War...