Andrew Vachss...
http://www.vachss.com/
Andrew Henry Vachss (born 1942) is an American crime fiction author, child protection consultant, and attorney exclusively representing children and youths. He is also a founder and national advisory board member of PROTECT: The National Association to Protect Children. Vachss coined the phrase "Children of the Secret," which refers to abused children, of whatever age, who were victimized without ever experiencing justice, much less love and protection. In the Burke novels, some of these Children of the Secret have banded together as adults into what Vachss calls a "family of choice." Their connection is not biological, and their bond goes well beyond mere loyalty. Most are career criminals; none allows the law to come before their duty to their family.
Vachss novels feature the shadowy, unlicensed investigator Burke, an ex-con, career criminal, and deeply conflicted character. About his protagonist, Vachss says:
If you look at Burke closely, you'll see the prototypical abused child: hypervigilant, distrustful. He's so committed to his family of choice — not his DNA-biological family, which tortured him, or the state which raised him, but the family that he chose — that homicide is a natural consequence of injuring any of that family. He's not a hit man. But he shares the same religion I do, which is revenge.
– "Andrew Vachss," Horror Online, April 1999.
His Burke books all share a common theme, revenge against child molesters and those who would harm his family. I have often described Burke as a Travis McGee raised by the state in New York. Besides his drive to protect children Vachss also has the same drive to protect abused and abandoned dogs. This them is also present in his Burke books. I would recommend reading them in order as they are a progressive series and often refer back to earlier stories.