I enjoyed (Disclaimer regarding enjoyment, the books were a good read but the subject matter isn't really enjoyable.) her previous books, Freak and Creep. This book details the gestation of a serial killer and what results.
The villain is identified early in this book. That doesn't matter as far as the creepy factor. The story is well crafted with an excellent plot line. The characters are believable. The bizarre intertwining of the characters provides and additional level of complexity that enhances the story value.
Ms. Hillier provides an excellent read with substantial tension and concern over the eventual outcome.
I recommend the book.
Web Sites: http://www.jenniferhillier.org/
This book may have been received free of charge from a publisher or a publicist. That will NEVER have a bearing on my recommendations.