Help me identify this book please?!?

Like five years ago or so, I read a book about spies and world war two and Auschwitz and the like. What I remember from the book is that there was a shoemaker who was at the camp, a lady in a cabin, someone was tied to a stake or something and had dogs attack him, and some guys who had to climb a wire and defuse a bomb type thing (I think?) I'm pretty sure there was an evil doctor as well. That's about all that I can recall and I'm fairly certain the title had the word "cross" or 'mark' in it. The cover was black with the title at the top and the symbol of a bird carrying a medal with a swastika or something of the sort.

I know these details are few and possibly inaccurate, but any ideas would be greatly appreciated. I can't figure out the book for the life of me and it's driving me insane.

Please and thank you!(: