Purgatory

An Irish ex-cop is lured into a violent game by a vengeful killer in this “excellent” crime novel by an Edgar Award finalist (Publishers Weekly, starred review).
 
Former cop Jack Taylor is recovering from mental and physical wounds, as well as from addictions to a variety of substances. But this fragile existence is threatened when a vigilante begins targeting the scum of Galway, signing mysterious notes with the moniker “C33.” The murderer addresses these cryptic letters to Jack, trying to goad him into joining the violent spree.
While Jack tries to unravel the mystery and motives of this demented killer, he’s also brought into the fold of an enigmatic tech billionaire who has been buying up massive amounts of property in Galway, seemingly in the hopes of offering this downtrodden city a better future. Yet if Jack has learned one thing living in Ireland, it's that people who outwardly claim to be on the side of righteousness are likely harboring far more nefarious motives beneath the surface.
With the help of his friends, a former drug dealer-turned-zen master and a dogged police sergeant, Jack is determined to track down C33, even if it jeopardizes his livelihood, his friends, and the remaining shreds of his sanity…
 
“Noir fans will find what they love here.”—Booklist (starred review)