John Lutz: Darker Than Night (USA 2004)
From the Publisher:
Enter ex-homicide cop Frank Quinn, still reeling in the wake of an elaborate setup that ended his career. For Quinn, this isn't just any job -- it's a last chance to salvage his reputation. As the investigation proceeds, the murderer loses no time stalking new prey: a loan officer and her high-earning husband; a couple who made a killing in the stock market; a pretty actress and her prosperous lover.
With the body count rising, it's up to Quinn to unlock the mystery of a madman's past and end his bloody reign. Quinn's got his work cut out -- because in a city the size of New York, any one of 8 million faces could be that of a killer -- or his next target...
John Lutz: Darker Than Night. Pinnacle Books; ISBN: 0786016337 (November, 2004), 541 p., $6.99.