wikipedia:

Caril Ann Fugate (born July 30, 1943) was the adolescent girlfriend and accomplice of spree killer Charles Starkweather. She is the youngest female in United States history to have been tried for first-degree murder.

The Starkweather–Fugate case inspired the films The Sadist (1963), Badlands (1973), Kalifornia (1993), Natural Born Killers (1994) and Starkweather (2004).