THE GOOD DETECTIVE by John McMahon

Since the night his wife and son were killed in an accident, Detective P.T. Marsh can't see the line between bold moves and disastrous decisions. But when the former rising star of the Mason Falls, Georgia, police force decides to help out a woman by giving her abusive boyfriend a taste of his own medicine, he might have crossed a line. The next morning he gets called to the scene of his newest murder case, and is stunned to arrive at the house of a dead man, the very man he beat up the night before. As P.T. and his partner, Remy, begin to suspect the murder is connected to a local arson and the lynching of a teenage boy, P.T. realizes he might have killed the top suspect of this horrific crime.