A deeply traumatic event in Joseph DeAngelo's childhood involved witnessing two soldiers rape his younger sister, Connie, in Germany when he was 10 years old. This experience is presented as a potential significant factor influencing his later violent and sexual offenses.
Impact: High. This reveals a profound childhood trauma that could serve as a foundational element in understanding DeAngelo's psychological development and eventual criminal behavior.
In the source video, this keypoint occurs from 02:55:33 to 02:56:35.
Sources in support: Megyn Kelly (Host)

