But even at a very young age, Samantha had a mean streak. When she was about 20 months old, living with foster parents in Texas, she clashed with a boy in day care. The caretaker soothed them both; problem solved. Later that day Samantha, who was already potty trained, walked over to where the boy was playing, pulled down her pants, and peed on him. “She knew exactly what she was doing,” Jen says. “There was an ability to wait until an opportune moment to exact her revenge on someone.”

Source: When Your Child Is a Psychopath – The Atlantic