While the basic premise for the book is a good find that creates a nice variation on the serial killer theme the actual description of events is very poorly realised.

The characters have absolutely no depth, even the central actor Joona is only presented by short flashes that explain nothing, least of all any motivation for any of his actions.

The sequence of events as well as the events themselves make no sense.

One example would be where the police decides to introduce a double agent to try to get some info out of the killer, knowing that he has been kept in strict isolation for 17 years without talking to anyone. Let alone the fact that no matter the mental deterioration of the patient he would be suspicious of anyone new introduced in his company after having been alone for so long, the police expects him to open up to this new intruder in just a few days because one of his captives will die in a few days.

The rest of the novel is layed out in similar fashion, events occur suddenly without much explanation or motivation and again don't count on characters' foundation for justification as those characters are just cardboard mannequins without any substance whatsoever.