McKenna has just written "Manhattan North Homicide: The True Story of One of New York's Best Homicide Cops." In his 30 years with the NYPD, he's worked on some of the cities most infamous cases and he describes them in the book: The Central Park Jogger Case, The Preppie Murder Case, The Brooklyn Bridge Shootings, and The Baby Maldonado Case. McKenna worked his way up as a uniformed patrolman to detective first grade to Manhattan North homicide--an elite force within the NYPD.