Only Killers and Thieves by Paul Howarth
In this Australian western, brothers Tommy and Billy return from a day of goofing off to find their family brutally murdered. Taken in by their rich neighbor, Sullivan (who their father could not tolerate), the boys are persuaded to join in pursuit of a group of aboriginal people, one of whom they suspect. What ensues is nothing they could ever imagine, the aftereffects of which will follow them the rest of their lives. A very good page turner.