For six years, a serial killer prowled the streets of New York City. He wrote letters to police and "The New York Post," indicating he would kill twelve people, one for each astrological sign. Forensic astronomy, handwriting analysis and DNA extracted from the flap of an envelope gave investigators a profile of the killer. Originally aired as Season 8, Episode 25.For six years, a serial killer prowled the streets of New York City. He wrote letters to police and "The New York Post," indicating he would kill twelve people, one for each astrological sign. Forensic astronomy, handwriting analysis and DNA extracted from the flap of an envelope gave investigators a profile of the killer. Originally aired as Season 8, Episode 25.