The Matt Scudder mysteries - Lawrence Block

The Sins of the Fathers
A murdered prostitute's father wants the investigation into her death re-opened. And Matt Scudder is lured into a sordid world of phoney religion and murderous lust where children must die for their parents' most secret sins.

In the Midst of Death
NYPD cop Jerry Broadfield has turned on his own, collaborating in a Special Prosecutor's investigation into police corruption. It's a move that lands him in a jail cell on a murder rap.

Time to Murder and Create
The Spinner was a petty crook and a blackmailer, but that didn't give someone the right to bash his head in, throw him in the river and walk away. At least not according to Matt Scudder's code of honour