Saints of New York: R.J. Ellory

Most cops are trying to right grievous wrongs. Few, however, have to deal with the horrific crimes of their own father...
Frank Parrish had a famous father: a Saint of New York, an NYPD detective who helped rid the city of Mafia control in the 1980s. John Parrish is a tough act to follow - a legend in his own right - and Frank already has an insubordination rap to beat.
Summoned for daily Police Department interviews, he's also trying to work out how the death of a young heroin dealer might connect to his innocent teenage sister, who's just been found dead.
There are more questions than answers, not just as the homicides escalate, but as Frank battles with his own demons. He must find the truth, and bring the trail of murder to an end.