The Dark Hours by Amy Jordan - a debut thriller set in Cork

In this debut, a retired detective is forced to revisit her most traumatic case when two young women are killed in eerily similar circumstances. Retired Garda Julia Harte lives modestly in a secluded Irish village with her dog, trying not to think about the murderer who destroyed her life back in 1994.  Even when she learns he died in prison, Julia cannot relax and she is startled to get a call from her one-time chief superintendent, Des Riordan. He asks her to return to Cork to help with the new investigation, in case it is a copycat crime.