Those Who Wish Me Dead by Michael Koryta
A high adventure murder mystery. Young Jace is witness to murders at the abandoned quarry just behind his house. His parents send him to a mountain wilderness survival program run by Ethan Serbin and his wife Allison. It is fire season in those mountains and the brutal Blackwell brothers have more than a boy to contend with when they hunt down the witness who could put them away.
Very good and an easy read.