Background about the Zodiac Killer, "one of the great unsolved serial killer mysteries of all time. ... This October, 1966 killing began a ghoulish series of murders that panicked the people of the San Francisco area. For years the Zodiac taunted the police with weird ciphers, phone calls, insulting and cryptic messages." Includes example of cryptograms, discussions of evidence and the case against Arthur Allen (a suspect), and more. From CourtTV.