Another good one, continuing the 'Irish Western' conceit of The Searcher complete with the prospect of gold in the hills and centring both Trey and Lena Dunne alongside transplanted Chicago cop Cal Hooper, which is a good choice. The depiction of Ardnakelty and its wily, slippery community is the highlight, embodied especially in Cal's neighbour Mart - French is very good on the unspoken communication and codes of rural (semi-remote) village life and the dangers it poses to those who step outside accepted behaviour, without ever slipping into faux-gothic mode.
I could've done without the sustained dramatic irony of Trey and Cal working at cross purposes for much of the book, but it did have the effect of highlighting the way that personal 'codes' can drive choices and behaviours, potentially tragically - and some of the later twists were satisfying surprises, especially the revelation of the murderer, which was a nice thematic contrast and complement to The Searcher's resolution.