Our first female serial killer, Juana Barraza, aka The Little Old Lady Killer! Her whole story is packed into just one episode (since we don't read/speak Spanish, and she didn't talk much)!
Sources:
The Little Old Lady Killer: The Sensationalized Crimes of Mexico's First Female Serial Killer. By Susana Vargas Cervantes
Murderpedia.com
Juana Barraza criminal minds wiki
