This book was a great read for many many reasons of which I shall list below.

It keeps me guessing as to who was the serial killer/murderer, who was the assassin and who was the crazy nut that kept terrorizing people.

I love the variety of strong female characters in this book and I am one who is a sucker for 'em. The female characters in this book are strong in a sense that they are all intelligent in where they know how to apply their strong suits to defeat the enemy.

Most of the main or key characters have some flaws in them which makes them an even more awesome character to read about. For example: (There are others but I thought I'd list down a few)
* Anna Wolff: She is strong and fearless yet she has anger management issues

*Jan Fabel: He is a gentleman but being a gentleman stands in his way in this book for him to properly analyze the female killer(s)

*Margarethe Paulus: Smart, beautiful yet pyschologically unbalanced

I also liked how the POV changes throughout the book from the serial killer to the assassin to Jan Fabel and how it seems to be messy and unorganized at first but as you read through it all starts to fall into place and connect with each other

After reading this I realized that this is the 5th book in a series. LIKE WHAT?! No wonder the book never answered about this one subordinate that Jan had who had a mental breakdown. I was like waiting and waiting for it...