Dead Witch Walking (Rachel Morgan, Book 1)

"All the creatures of the night gather in "the Hollows" of Cincinnati, to hide, to prowl, to party... and to feed. Vampires rule the darkness in a predator-eat-predator world rife with dangers beyond imagining - and it's Rachel Morgan's job to keep that world civilized. A bounty hunter and witch with serious sex appeal and an attitude, she'll bring 'em back alive, dead... or undead." (goodreads.com)