Enemy Within — Robert K. Tanenbaum

New York: The city erupts in chaos when a black man is shot in the back by an NYPD "golden boy" street cop. As chief assistant district attorney Butch Karp soon discovers, certain higher-ups would rather whitewash the truth than lose votes in the upcoming election. To make matters worse, a serial killer is on the loose, stalking his prey near where Karp's daughter, Lucy, is helping feed the homeless. Desperate to stop the violence before it touches his family, Karp must wade through a system of corruption and conspiracy that threatens to silence his pursuit of the truth ... forever.