Booked To Die by John Dunning

Denver homicide detective Cliff Janeway may not always play by the book, but he’s an avid collector of rare and first editions. Bobby Westfall is a local bookscout, a gentle and quiet man who has sold enough valuable books to keep himself and his cats fed and housed. When Bobby is murdered, Janeway would like nothing better than to rearrange the suspect’s spine. But the suspect, local lowlife Jackie Newton, is a master at eluding the law, and Janeway’s wrathful brand of off-duty justice costs him his badge.

Turning to his lifelong passion, Janeway opens a small bookshop—all the while searching for evidence to put Newton away. When prized volumes in a highly sought-after collection begin to appear, so do dead bodies. Now Janeway’s life is about to change in profound and shocking ways as he attempts to find out who’s dealing death along with vintage Chandlers and Twains.