Oskar Gröning

He died age 94 before he could begin serving his sentence for his role in Auschwitz. He was a bookkeeper. He was sentenced in 2015 to being an accessory to murder of 300,000 Jews, and, his appeals having failed, was about to be imprisoned when he died.

Wikipedia has his story. One might ask why the authorities waited so long to try him. He was charged based on his own testimony--he couldn't stand Holocaust deniers, and told of where he had been and what he had seen. He considered himself relatively innocent--he had never been more than a bookkeeper, and had tried to leave.

Read his story. He's an interesting mix of self-deception and integrity.