True Crime, Mystery 

The three teenagers found in a wooded Texas park suffered slow torture with a knife before dying. A usually implacable cop who arrived early on the scene, Truman Simons, was so shaken by the lonely, abandoned appearance of their naked bodies that he got down on his knees next to one of the girls and promised he would find her killer. But he wasn't part of the initial investigation, which exhausted all leads and was labeled "inactive" after just 52 days. Simons begged his superior to be allowed to investigate on his own, slowly tracked down a few pieces of the puzzle, then was asked to drop the case after a suspect he'd arrested was set free. He then did what few cops would do: he quit the police department, took a job as a jailer, and pursued the case on his free time, eventually forming an oddly intimate jailer-suspect relationship with one of the killers. Careless Whispers won the 1987 Edgar Award for best fact crime. - from Amzon