The UnXplained: The Zodiac Killer's Deadly Code Explored (Season 6) | History

[0:02]San Francisco, California, July 31st, 1969. The city is gripped by fear after a number of horrific and unsolved murders are committed by a shadowy serial killer. The panic reaches a fever pitch when the killer releases a series of chilling notes. In which he refers to himself, as the zodiac. Three virtually identical handwritten letters arrived at the offices of three California newspapers. And those letters took credit for the crimes and included details from the crimes, including the ammunition that was used, the positions of the victims and things like that. And then another letter that was sent on August 4th of 1969, was the first to use the name The Zodiac. The Zodiac's crime spree is often referred to as a reign of terror. And that's because his murders not only sent fear throughout the community, but he eventually threatened to murder school children on a bus. He also said he was going to use a bomb. So there were a lot of threats that sent fear through the community. His name really got out there and on top of that, Zodiac's victims were selected presumably randomly. And so people felt like, well, he could be around the corner, ready to kill me or us. So he became kind of like a boogeyman, waiting to kill somebody. The Zodiac as macabre as it sounds, turned his killings into a game. Not just for law enforcement to try to figure out, but for the average citizen. These ciphers sort of served as a way for people to play his game. Can you figure out who I am? So, using these codes, while it made Zodiac incredibly scary, it also made him intriguing because anybody could figure out who the Zodiac Killer is if you know how to play his game correctly. The Zodiac's claim that the ciphers revealed his true identity, taunted the police and the public. Both the authorities and amateurs alike poured over the encrypted letters, hoping to crack the killer's devious codes. The first cipher of the Zodiac, it's commonly referred to as the 408 cipher. That was actually solved in a matter of days by a couple of citizens in the San Francisco Bay Area. a local high school economics teacher and his wife, Donald and Betty Harden, decided to take the killer's challenge and spent a weekend trying to solve that cipher. And they were able to find the solution. Unfortunately, the harden solution did not reveal the killer's identity. But it did begin with the phrase, I like killing people because it is so much fun. Then he talked about collecting slaves for his afterlife. The shocking content of the first cipher heightened public panic about the Zodiac. But the killer's second cipher, known as Z340, would not be solved so easily. The Zodiac's second cipher consisted of 340 symbols. Unfortunately, that cipher was very difficult to solve, and he may have made it that way deliberately, because he may have been upset that his first cipher was solved so quickly. Despite years of effort, the Z340 cipher eluded decryption. By 1974, the Zodiac had released more than 20 letters. In which he claimed to have killed 37 people. And then, after a five-year reign of terror, his communications abruptly ceased, and the case went cold. It seemed that the codes and the crimes of this evil genius, were destined to remain unsolved. More than 30 years would pass before software engineer David Oranchak became inspired to take on the Z340 cipher. To try and solve the cipher, David Oranchak teamed up with Australian mathematician, Sam Blake, and Belgian computer programmer, Jan Van Ike. The team became kind of this collaboration of people that would run experiments, try out different ideas, come up with computer programs and different kind of specialized tools. In order to try out these ideas or to just run a bunch of keys and try to break the code. In spite of their combined efforts, the Z340 cipher seemed like it might be an unbreakable code. But then, after 15 years of challenging work, the team finally cracked it. It was very satisfying to decrypt the message. It was very exciting. Once we had the solution, I put together a report and sent it to my contacts in the code breaking unit of the FBI. And then very quickly, they came back to us and said, this looks good, looks strong, looks like the real solution. And that's when the media storm hit. The revelation that the Z340 cipher had been broken, more than 50 years after it was released made headlines around the world. But unfortunately, the decrypted message did not reveal the killer's identity. However, the search continues. Because there are other Zodiac ciphers that are yet to be solved. The most fascinating of which is called Z13. This cipher will literally make you pull your hair out. Because at first glance, you would think it's got to be easy. There's only 13 characters in this cipher. What's worse is that it starts with the phrase, my name is. He's literally telling you, here's who I am. And to this day, no one's been able to figure it out as of yet.