Burnt Offerings (Anita Blake Vampire Huntre #7) by Laurell K. Hamilton

YOU CAN'T TRUST ANYONE WHO SLEEPS WITH THE MONSTERS.

That's what I've always said.   That's what I've always believed. But now I'm the one sharing a bed with the Master Vampire of the City. I'm Anita Blake, the woman the vampires call the Executioner.
From part of the solution, I've become part of the problem.

So it hits close to home when an arsonist begins to target vampire-owned businesses all over town - an arsonist who seems to want to destroy more than just property. It's the monsters who are in danger now. And it's up to the Executioner to save them from the inferno.