Dead and Gone by Charlaine Harris (Sookie Stackhouse #9)

The vamps have been out for years, and now the weres and shifters have decided to follow the lead of the undead and reveal their existence to the ordinary world. Sookie Stackhouse already knows about them, of course - her brother turns into a panther at the full moon, she's friend to the local were pack, and Sam, her boss at Merlotte's bar, is a shapeshifter.
The great revelation goes well at first - then the horribly mutilated body of a were-panther is found in the parking lot of Merlotte's, and Sookie agrees to use her telepathic talent to track down the murderer. But there is a far greater danger than this killer threatening Bon Temps: a race of unhuman beings, older, more powerful, and far more secretive than the vampires or the werewolves, is preparing for war. And Sookie is an all-too-human pawn in their ages-old battle ...