Footsteps of the Hawk — Andrew H. Vachss

A pulse-quickening new crime novel featuring Burke, ex-con, private investigator, and rumored hit man who harbors a pathological hatred for those who prey on children.
In Footsteps of the Hawk Burke himself is in danger of becoming a victim. Two rogue cops are stalking him. The coolly seductive Belinda Roberts wants him to free a man charged with a grisly string of rape-murders. The brutal and half-crazed Detective Jorge Morales may be trying to frame Burke for the same crimes. What ensues is a novel of high-wire suspense and nightmarish authenticity informed by an insider's knowledge of the city where everything … from flesh to other people's cellular phones … is up for sale.