«Past Due» by William Lashner

A defense attorney who lives his life in shades of gray, Victor Carl fights all the right fights for all the wrong reasons. With a failing legal practice, a dead-end love life, and a pile of unpaid traffic tickets, Victor skates on the razor's edge of legal ethics in search of the easy buck. But the one absolute in Victor's life is loyalty, especially to a client – even if he happens to be dead. Like Joey Cheaps, a no-account who takes a knife to the throat down on the waterfront, but not before he shares with his lawyer his part in a terrible crime.
With his client murdered, Victor must search for a killer. But solving the crime means investigating the darkest spot in Joey Cheap's misspent youth, sending Victor on a twisting journey that leads to a missing suitcase stuffed with money, photographs of a mysterious naked woman, and a Supreme Court justice with a secret to hide. And most dangerous of all, Victor steps into the crosshairs of a vengeful enemy with a past full of pain and a taste for blood.
As thrilling as it is darkly evocative, Past Due is a superb tale of crime and justice that takes the intrepid Victor Carl into brilliant new territory and confirms William Lashner's place among the top suspense writers of our time.