Where it hurts - Reed Farrel Coleman

Gus Murphy, a retired cop, had everything a man could want: a great marriage, two kids, a nice house and the rest of his life ahead of him. But when his family is blown apart, he is transformed from a man who believes he understands everything into a man who understands nothing. Divorced and working as a courtesy van driver, ex-con Tommy Delcamino comes to him for help. Months earlier, TJ Delcamino's battered body was discovered and the police don't seem interested in finding the killers. In desperation, Tommy seeks out the only cop he ever trusted - Gus Murphy.