Law and outlaw — William Vance

The old woman was dying. That meant a lot of things to Will Titus. It meant sorrow, for she'd raised him from a pup. It meant one fewer good person in a world where they were rare enough already. But mostly, it meant the eventual arrival of Bart Laney. Bart was almost a brother to Will - but a brother gone wrong. While Will had chosen a U.S. Marshal's badge, Bart had gone down the outlaw trail...