Ride the Savage River — Scott Connor

Marshal Ellis Moore had been cleaning up Empire Falls for twelve years, but is killed taking on the last of the gun-toters who control his town. At the funeral, Moore's sons learn that he had been on the payroll of Samuel Holdstock, a notorious villain who is now spreading his corrupting influence downriver. Daniel and Henry vow to put right their father's mistakes and deliver Holdstock to justice - a mission even the formidable US Marshal Lincoln thinks is doomed to fail.