'Skin Trade' by Laurell K. Hamilton

Skin Trade by Laurell K. Hamilton is the seventeenth book in the Anita Blake Vampire Hunter series, which started with Guilty Pleasures. Anita Blake is a vampire hunter in a world where vampires are protected as long as they behave. In Skin Trade, Blake is called in to deal with some serious misbehavior in Las Vegas -- 10 officers and one executioner already dead by a vampire serial killer. When she gets there, Blake senses that were-tigers are involved, making the whole ordeal much more dangerous for her.