New York 'Zodiac' Killer Followed A Distinct Pattern

New York investigators learned that the Zodiac killer was following a distinct pattern and struck every 21 days on a Thursday. On June 21, 1990, a homeless man who had been sleeping on a bench in Central Park was shot by a man after telling him his astrological sign. At the park, detectives found a note with their killer's mark and a fourth sign in the zodiac wheel — Cancer.