Patricia Briggs's latest novel Fair Game is the third in her "Alpha and Omega" series but is relevant here since the main characters are called in to consult with the FBI (not BAU, curiously) on a serial killer case that has taken a turn for the paranormal.

If you're not familiar with the series, the main characters are werewolves.

The "Alpha and Omega" series is a spinoff from the "Mercy Thompson" series, but this one would probably stand alone pretty well if you're in it for the FBI bits and not for the paranormal romance bits. I'd recommend both series if you can stomach the paranormal bits. They're not high art, but Briggs writes well-rounded characters and page-turner plots that I at least find entertaining.

I've read the first three Mercy Thompson books and enjoyed those. I'll have to check out the Alpha and Omega ones as well.

Thanks for the heads up. I'll definitely hit the Alpha and Omega books soon.