The Searcher is another gripping book from Tana French which had me hooked from start to finish.

Ex cop Cal Hooper moves to a remote Irish village after his divorce, hoping to get away from everything. Instead he finds himself sucked into local life when a teenager enlists his help to track down their missing brother.
Nothing it quite what it seems in the village, and even the friendly locals aren’t telling Cal everything. His own code won’t let him drop the investigation even when it becomes darker, even when he is put in danger.

Well worth reading to uncover all the secrets.