And, if you don't mind to read teen books, I recommend R.L. Stine. His books are a little bit naive, but interesting.
You can also read H. P. Lovecraft's Dagon.
What about Umberto Eco's In the name of the rose? Or Death in holy orders by P.D. James? You may be interested in Philip Vandenberg's Forgotten pergemant too. And Monaldi & Sorti's trilogy Imprimatur, Secretum, Veritas.
I don't know if you are still interested in WW2 books, but I'll anyway recommend the one.
Sadako wants to live by Karl Bruckner
It's about the girl from Japan. She lived in Hiroshima when was the A-Bomb dropped.