Shadow Season — Tom Piccirilli

An ex-cop, Finn was left literally blinded by violence. The one thing he "can" still see is the body of his wife, Dani, and a crime scene that won't fade from his mind's eye. Now a professor, Finn never would have guessed that an isolated girls' prep school could be every bit as dangerous as city streets. Especially when he stumbles upon a local girl lying in a graveyard in the middle of a raging blizzard.
Finn may live in a world of total darkness, but it's about to get a splash of red. The memories that torment him still have the power to kill, and a group of innocent students has been put in harm's way by a pair of vicious criminals stalking Finn for unknown reasons. Secrets are creeping from the shadows around him--the kind that even a man with perfect vision never sees until it's too late. They're about to become terrifyingly clear to Finn--and it all begins with the scent of blood.