On the Ropes by Tom Schreck

Duffy Dombrowski is not your average social worker. When he's not counseling sex addicts and drug users in a town outside of New York City, you can find him crooning Elvis tunes, getting "Schlitzed" with his quirky friends, or fighting ex-Olympians in the boxing ring. Our less-than-perfect hero occasionally uses his mean left hook on pimps and other lowlifes, too. But at least he cares about his clients.
When Walanda, a schizophrenic, crack-addicted prostitute, is murdered, Duffy pledges to take care of her basset hound "Allah King" and find her missing stepdaughter, Shony. He's horrified to discover the teenager is ensnared in a web porn ring-a vile enterprise that enslaves crack-addicted women and their children.
On the verge of losing his job-and his life-Duffy also gets mixed up with a creepy doctor with ties to Pakistani extremists. Still, nothing will stop this conflicted Robin Hood from trying to save Shony and foil a terrorist plot.