Be still my Vampire Heart ~ Kerrelyn Sparks

This is the third in the vampire series. Angus is the head of a security company that provides security for many of the big vampires, the heads of different covens. And a friend of Roman's. When the head of the Russian Coven threatens Roman with a vampire war if another of her vampires is killed, Angus comes to investigate what is happening. Emma is a member of the CIA Stake-Out unit, and actively hunting all vampires, to the point of stalking Central Park at night to stake vampires. Angus discovers who is responsible for the vampire slayings and does his best to protect her.