Blood Bound - New Orleans Trilogy, #1

Fueled by grief after his fiancée is brutally murdered, Detective Sam Walker focuses on finding her killer-a calculating predator who binds books with human skin. Dani Barrington, the newest member of NOPD's Victim and Witness Assistance Unit and a survivor of another frightening attack, helps him discover the terrifying link between the monster's known victims. Despite his anguish, Sam is struck by Dani's incredible strength and determination, especially when her inquisitive  nature makes her the killer's next target.
He must find a way to protect her or risk losing the one woman who can bring his dead heart back to life.