I read Pretty Little Dead Things with shivers down my spine. It’s that kind of book: Gary McMahon creates suspense and no small amount of dread as he introduces us to Thomas Usher, a sometime private investigator who sees dead people. Usher becomes mixed up in a series of grisly murders that all point to something much more sinister going down (yes, more sinister than murder). And he isn’t the only one who is slinging…