It took 51 years to crack, but one of the taunting messages written in code and attributed to the Zodiac Killer has been solved, according to the FBI.The Zodiac Killer is most known for leaving a trail of five unsolved murders between 1968 and 1969. He was never caught, but he gained notoriety by writing letters to police and local media up until 1974, sometimes in code, boasting of the killings.TUNE IN NOW