Vow of Evil — Veronica Black

It's been some time since Sister Joan of the Order of the Daughters of Compassion has had to solve a murder, but there are indications that will soon change. Outbreaks of vandalism in the village coincide with the sighting of a devil in the churchyard and strange candles left burning in the postulancy, now rented out to the Lurgan family. Then it is that Sister Joan finds a body, a young police officer goes missing and old Sister Gabrielle begins to act in a most furtive manner. Evil draws ever closer in the vengeful search for victims.