There are lots of books by people imprisoned in Nazi concentration camps, but...

Not exactly what the OP is looking for, but the film Blind Spot is a feature-length interview with one of Hitler’s secretaries conducted a year or two ago, a few months before her death. She was in the bunker with der Fuehrer during the last days and everything. Fascinating stuff. She was obviously deeply haunted by her passively denied ignorance of what she was participating in.