About a decade before Richard Ramirez gained infamy as the “Night Stalker” serial killer, the chilling statement, “There’s no thrill like a good kill," had made an indelible impression on him.

The assertion was made by an older cousin, according to Richard Ramirez: The Night Stalker Tapes, now streaming on Peacock. The docuseries details how Ramirez grew up surrounded by disturbing ...