Close Range by Paul Heatley

Former special-forces operative Tom Rollins is arrested in rural Pennsylvania on a fabricated charge after crossing paths with two corrupt police officers. His combat skills attract the attention of powerful local figure Sebastian Husky, whose troubled teenage nephew Jack has disappeared in the dangerous Furnace Mountain area. Tom agrees to find him, expecting a simple rescue mission, but soon discovers that moonshiners, corrupt police, hired killers, and a deadly sniper are all hunting the boy. As Tom tries to keep Jack alive, the mountain becomes a deadly battlefield where survival depends on his ability to outfight everyone coming after them.