Cruel Justice is the first book of six in the Justice series.
http://www.amazon.com/Cruel-Justice-Book-ebook/dp/B005QOY4FM/ref=pd_sim_kinc_6 Set in the UK it follows the adventures of DI Lorne Simpkins and her partner DS Pete Childs who are on the hunt for a psychotic serial killer.
When a family member's life is put at risk by the killer and clues few and far between, Lorne has to turn to an unlikey source to help her save this heinous case.