The fact that a book is promoted doesn’t mean it’s any good. This one isn’t.
The hero is a Mary Sue. The youngest in the Service, bla-bla. Shoots his boss because he’s working for the Russians. Gets his job. Yeah, right. Also, he’s the adopted son of a millionaire, so it’s not an issue for him to retire at 30 and do whatever he likes. Like writing the best book about criminal investigation ever. Because why not.
Storytelling is amateurish. The author wanted to tell the story from the first person, but then decided he needed to tell another story from 10 years ago, which is supposed to be based on accounts of interrogations, but contains details nobody would mention, like what was going on in the head of a terrorist, or his soon-to-be dead victims. Amateurish.