Death In Paradise by Robert B. Parker

Chief of Police Jesse Stone returns to investigate the murder of a troubled teenager in a seemingly bucolic New England town. The Paradise Men's Softball League has wrapped up another game, and Jesse Stone is lingering in the parking lot with his team-mates, drinking beer, swapping stories of double plays and beautiful women in the late summer twilight. But then a voice, scared, calls out to him from the edge of a nearby lake. He walks to the sound, where two men squat at the water's edge. In front of them, face down, is something that used to be a girl. The local cops haven't seen anything like this, but Jesse's LA past has made him all too familiar with floaters.