The Last Teacher (Mackenzie August #0.5)

Mackenzie August is starting a new life. After a successful but destructive career as a high-profile California homicide detective, and then a less successful and even more destructive stint working for a church, he has moved to Virginia to start over as a teacher. The only thing he's bringing with him is Kix, his infant baby boy. He plans for peaceful living with his son, but trouble soon finds him as his new co-workers begin showing up dead outside of his classroom. The Sheriff's Office is stumped, the teachers are scared, and hidden rifts within the county begin surfacing. The town turns to August for help, which he is compelled to provide after learning that evidence suggests he will be the next victim. August must survive entanglements with the small-time police force, a local drug dealer, and the young and aggressive brunette teaching across from him if he is to stop the mysterious killer.