If you like ax murder movies you would probably consider this book (and the whole series) rather tame. If, however, you like a "thriller" to focus more on the detective work and the "profile" of the criminal with just enough details of the violence to bring a touch of reality to the story, this will be a good choice for you.
At the beginning of the series I thought Bowers was supposed to be a Christian. Now I'm not so sure. Certainly, he is a bit confused about some things if he is. The stories aren't filled with people quoting scripture or demonstrating a serious and mature relationship with Christ. Instead, they are filled with people who are leading messed up and/or painful lives but who are searching for a way to a better life and to relieve themselves of guilt they carry from past experiences. The books are not filled with people "sleeping around" or cursing or taking God's name in vain. This is something I appreciate. Life is messy. For Christians as well as non-Christians. Everyone experiences unpleasant situations in life. But not everyone chooses to sink to the lowest standards in every situation.
Well, before I start getting too philosophical I'd better stop writing. I enjoyed The Queen as I have all the other books in the series. I recommend it; though not late at night if you tend to have nightmares.
Happy reading. :D