The Santa Killer | 
pickBook 6 in this series. Beware of Santa ...
17 likes
Final book in a series. British police procedural. I read the first, for intro to the investigators then skipped to this one for the seasonal theme. The prose isn't going to win any awards, but the plotting was tight in both books. And twisty. The characters are well done; both the cops, the victims, and the suspects. Will probably return to the series the next time I want a serial killer murder mystery.