The emerald lie / Ken Bruen.

The latest terror to be visited upon the dark Galway streets arrives in a most unusual form: an Eton and Cambridge graduate who becomes murderous over split infinitives, improper punctuation, and any other sign of bad grammar. Meanwhile, ex-cop Jack Taylor is approached by a grieving father with a pocketful of cash on offer if Jack will help exact revenge on those responsible for his daughter's brutal rape and murder. Jack reluctantly agrees, but is soon derailed by the reappearance of Emily, the young woman who joined forces with him to take down her paedophile father. She is ready to use any sort of coercion to get Jack to conspire with her against the serial killer the Garda have nicknamed "the Grammarian", but her most destructive obsession just might be Jack himself...