I was sent this book in return for my honest unbiased review. 3 1/2 stars rounded to 4 Retribution is a full-on police procedural which reflects a lot of brilliant research. I did feel that I had missed out not having read books 1 & 2 as relationships between the characters has obviously been developed there. However having said that, this can be read as a standalone, making sense in its own. The story is very detailed - at times I could have done with less detail (I didn’t need full names and rank of officers every time or address of the different police stations) The characterision is clear with each character having their own traits and attributes, however I didn’t feel an emotional attachment to any of them. The atrocities in the story were gruesome and detailed, working well with the horrific nature of the crimes. The plot cleverly covers several stories which share threads but no clear connection, when the police team start investigating. It must have been a mammoth task to develop them all and start to weave them together. I enjoyed reading this story, and learnt a lot about things like county lines, but after such a lengthy tome, the ending came too fast and, for me, a bit disappointing as it didn’t tie up all the loose ends, too many things I still needed answers to, although definitely open for a follow up.