Video: 'The Zodiac Killer - Serial Killer Documentary' (Dec. 20, 1968, at 0:38)

(Friday, December 20, 1968, shortly after 11:00 p.m. PST) — High school students Betty Lou Jensen and David Faraday were shot and killed tonight while parked along Lake Herman Road near Benicia, California, becoming the first confirmed victims of the Zodiac Killer, a serial killer who operated in Northern California from at least the late 1960s to the early 1970s.