One of my favorite authors is Ken Bruen who lives in Galway, Ireland. His Jack Taylor series is set in Galway and is steeped in Irish culture. There are currently seven books in this series and Sanctuary is the latest one.
This one breaks my "no serial killers" rule but this killer is different and not killing for the fun of it. Plus it clocks in at a thin 223 pages which is my kind of page count.