I haven’t read that one but after reading it's description on Amazon I can recommend another book.
Dimiter by William Blatty. And best of all it’s available as an ebook.
This is a book more along the lines of John leCarré. A little action here and there, but a lot of plot unraveling. As with leCarré keep alert for the small bits and pieces that'll be important later.
From eBooks.com;
“William Peter Blatty has thrilled generations of readers with his iconic mega-bestseller The Exorcist. Now Blatty gives us Dimiter, a riveting story of murder, revenge, and suspense. Laced with themes of faith and love, sin and forgiveness, vengeance and compassion, it is a novel in the grand tradition of Morris West’s The Devil’s Advocate and the Catholic novels of Graham Greene.”