J. R. Ward 
Envy 
Number 3 in series

Seven deadly sins. Seven souls to save. And a man and a woman treading the lines of danger, desire and deliverance . . .As the son of a serial killer, homicide detective Thomas ‘Veck’ Del Vecchio, Jr, grew up in the shadow of evil. Now, on the knife-edge between civic duty and blind retribution, he atones for the sins of his father – while fighting his inner demons. Assigned to monitor Veck is Internal Affairs officer Sophia Reilly, whose interest in him is both professional and arousingly personal. And Veck and Sophia have another link: Jim Heron, a mysterious stranger with too many answers . . . to questions that are deadly. When Veck and Sophia are drawn into the ultimate battle between good and evil, their fallen angel saviour is the only thing that stands between them and eternal damnation.