Monsters come in all shapes and sizes. They each have their reason for being the way they are, and you can bet very few of them actually think of themselves as monsters.
Erna was a young woman when she married SS officer, Horst Petri. When Horst was appointed to serve in L’viv in Ukraine, she moved to accompany him, managing the Grzenda Manor where they lived. In her early twenties, she mistreated the estate workers and developed a cruel nature while in her powerful position.
One day in autumn of 1943, on her way home from shopping, she saw six bedraggled boys dressed only in rags, by the side of the road. They ranged from approximately ages six to twelve. She recognized them as the Jewish children who had escaped a train car paused at the Saschkow station (which was headed to a concentration camp). She gathered the boys up, took them to her house, cleaned them up a little, fed and calmed them, and then took them into the woods behind her house and shot them in the back of the neck, murdering them.
She was eventually tried (found guilty) and sentenced to life in prison.