It's an m/m vampire novella called Bridge Over Troubled Water:
Detective Brady Lindstrom deals in death, and not just because he’s a homicide cop with the slaughter of a century to solve. Ten years ago, vampires murdered his lover. Ever since, he’s looked over his shoulder, ready for vampires to strike again. Or maybe just the one he loved.
Exhausted and angry about the needless deaths he has to investigate, Brady worries that the killers he’s looking for aren’t even human. Those fears are compounded by an unexpected visitor, the battered and nearly broken Cole Singer, the lover he’d long ago given up for dead. When Cole offers to trade information on the killers in exchange for sanctuary, Brady realizes he doesn’t have a choice. He just can’t turn his back on the face of the only man he’s ever loved. Even if he’s a vampire...
There's an excerpt at the site above, and today only, it's only $1.50. But you have to buy it through this link, not the blurb/excerpt page since it's part of the Daily Deal program.