Fool Moon by Jim Butcher
Synopsis from GoodReads:
Lost Items Found. Paranormal Investigations. Consulting. Advice. Reasonable Rates. No Love Potions, Endless Purses, or Other Entertainment.
Business has been slow. Okay, business has been dead. And not even of the undead variety. You would think Chicago would have a little more action for the only professional wizard in the phone book. But lately, Harry Dresden hasn’t been able to dredge up any kind of work–magical or mundane.
But just when it looks like he can’t afford his next meal, a murder comes along that requires his particular brand of supernatural expertise.
A brutally mutilated corpse. Strange-looking paw prints. A full moon. Take three guesses–and the first two don’t count…