Be Still My Vampire Heart Love At Stake Series, Book 3.

If it was still beating. Angus MacKay has been undead for almost five hundred years and it's not often something, or someone, surprises him. Until Emma Wallace. The sight of this luscious agent from the CIA's elite Stake-Out team was enough to stop Angus in his tracks. But then he discovers that she's a vampire slayer, intent on killing the "monsters" who killed her parents. And it's Angus's job to stop her. The only good vampire is a dead vampir...