“Goeie Mie” is the nickname of Maria Catharina Swanenburg. Goeie Mie died in 1915 but is known as the most prolific poisoner in the world. Historians suspect she killed over 90 people, and she might be the most infamous serial killer of the Netherlands. She was born and raised in Leiden, and killed family members and non-family members alike. Why did she do what she did? That’s unfortunately largely unknown. The papers that documented Goeie Mie’s trial did not come out of WW2 unscathed. All we know is that she did not have any regrets.