A Dark and Sinful Death — Alison Joseph

Attractive, stylish, not naturally saintly, Agnes Bourdillon isn't the kind of woman you expect to be a nun. And the expensive girls' boarding school in West Yorkshire where she's been sent to teach is hardly a place in which one would expect to find an art mistress as disturbed as Joanna Baines, discovered by Agnes in the artroom, surrounded by black paint and desecrated paintings.

Next day Joanna has disappeared from the school. And the day after that, a twenty-two-year-old gardener, Mark Snaith, is murdered on the moors nearby, his face horribly mutilated…

This is a brilliantly taut, superbly engrossing and compelling crime novel.