Who is the man that approached Corrie after she spoke in a church in Munich?

After speaking in church, Carrie approaches the former SS agent, who once stood guard in the shower room at Ravensbruck. Corrie is at first aghast and doesn't want to shake his hand, even after he tells her that he has found Christianity. She does, however, find the strength inside through God, giving him her forgiveness. The handshake affords them both with a much needed inner peace.