I think this is an excellent book, particularly for a younger readership. The sleuths are in their late teens and early twenties and use modern methods of detection, which are very interesting and entertaining to read. This book feels a bit like a modern famous five, a group of young friends solving crimes. There are two apparently separate crimes being investigated and also previous murders which at first seem to have been solved. A great many twists and turns in the plot lead to the surprising identity of the murderer and ultimate solution. There is a psychological aspect to the story as several characters are traumatised by both current and previous events and a vein of madness and pure evil.