Hunter's Kiss. Princeps Venator, #1

Michael Williams is no hero, he's just a cop who works a lot of burglary cases, ended up in the wrong place at the right time, and now he's known as the man who stopped the Harlem Vampire. Of course, vampires are a myth. Everyone knows that, especially Mike's rationalist girlfriend, Leanne. Mike stopped a serial killer with a blood fetish. Nothing to look at here, folks. Please move along. And then Mike meets Dione: stunningly attractive, strong, fast, intelligent, and Mike's new boss.
Together, Mike and Dione have the job of making sure that vampires remain mythical, even the ones walking the streets of New York.