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A killer's story - The Zodiac killer is one of the most infamous unresolved mysteries in history. He was responsible for seven attacks in Northern California in the late 1960s. The perpetrator of the murders said, however, that he was responsible for about 37 deaths.

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The first homicide - The first case occurred on 20 December 1968, when 17-year-old David Faraday and his girlfriend Betty Lou Jensen, 16, were shot dead in a car.

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The first homicide - The tragic event happened near Herman Lake, on a virtually deserted road just a few kilometers from the city of Oakland (San Francisco). Around 11 pm the couple is disturbed by a stranger carrying a gun.

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The first homicide - The killer starts firing into the couple's car and hits David Faraday in the head. Betty Lou Jensen still gets out of the car and flees the killer but is quickly caught and killed with five shots to her back.

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The first homicide - Minutes later, a local passer-by discovers the crime scene and calls the police. Locals and police officers were shocked. Who would kill two young people in cold blood for no apparent reason?

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The first homicide - This was the beginning of a wave of crimes that would haunt north San Francisco for more than 40 years, by a criminal who began to call himself 'The Zodiac Killer.'

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The second homicide - On 4 July 1969, two young people met at Blue Rock Springs Park (California). Darlene Elizabeth Ferrin, 22 and Michael Renault Mageau, 19, were surprised by a man who started shooting.

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The second homicide - Darlene Elizabeth Ferrin, 22, and Michael Renault Mageau, 19, were surprised by a man who begins to chase them until they reach Blue Rock Springs' golf course, where they were eventually shot.

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The second homicide - This time the Zodiac killer does something different. He steps away from the crime scene and calls the emergency services to report a double murder.

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The second homicide - The criminal indicates the location of the crime, the weapon used (Luger 9 mm), and still confesses to have killed the four young people. He terminates the call with a simple 'goodbye.'

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The second homicide - The young couple was shot several times. Darlene ended up dying, and Michael was fortunate to survive. The young man told the police that the killer was a white man, heavyset, wearing glasses, and between 26 and 30 years old.

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Mysterious letters - On 1 August 1969, Zodiac sent three nearly identical letters to three local newspapers: The San Francisco Examiner, San Francisco Chronicle, and the Vallejo Times-Herald. In each of them he detailed his crimes. A section of the letters had encrypted messages.

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Mysterious letters - The killer sent the letters to the newspapers because he wanted exposure, a typical trait of serial killers. The codes used in the cards when deciphered supposedly gave clues to the identity of the criminal.

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Mysterious letters - The killer threatened local newspapers that, if the letters were not posted on the front pages, he would continue to kill more victims. At the end of the messages there was always a common signature: a symbol (similar to a rifle scope) and that would become the signature of the Zodiac killer.

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Mysterious letters - The San Francisco Chronicle published part of the killer's cryptogram on the 4th page, challenging Zodiac's orders. The code was later deciphered but revealed nothing about the killer's identity.

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Mysterious letters - The code was about the killer's taste for killing and how his victims would become his slaves after his death. In another letter, Zodiac vowed that he would keep his promise to kill more victims.

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Third attack - The killer's third attack occurred on 27 September 1969, and the victims were Cecilia Ann Shepard, 22, and Bryan Calvin Hartnell, 20.

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Third attack - This time, the location was Lake Berryessa located near Napa, California. The Zodiac killer stabbed the couple several times and disappeared into the forest.

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Third attack - Just as with the previous case, Bryan Calvin Hartnell survives the attack, while Cecilia Ann Shepard ends up dying. The survivor describes the man to the police in the hospital bed saying that he was wearing a mask and seemed to enjoy the attack.

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The last murder - The last confirmed victim was 29-year-old taxi driver Paul Lee Stine, who was shot in the head on 11 October 1969 in north San Francisco.

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The last murder - Incredibly, the killer was almost caught by the police, but the description of a 'black adult' instead of a 'white adult' eventually confused the authorities.

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The last murder - Officers interrogated a well-built man (matching the description of the Zodiac) who told them he saw an armed man on the street where the crime happened. The killer later called the police to tell the authorities that they had crossed paths.

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Threat - After sending a letter confirming that he killed the taxi driver, Zodiac threatened to take down a school bus and kill the children as they would leave the vehicle. However, this threat was not confirmed.

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Sudden disappearance - After haunting the authorities and the public with about two dozen letters, the Zodiac killer hasn't been heard from since the late 1970s. However, the local population was terrified and always afraid that the mysterious killer might reappear.

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The last letter - In his last letter to the newspapers, the Zodiac killer claimed to be back and confessed, in addition to the seven official crimes, to have killed 37 people in total. The speculation was that he had left the country or that he was in jail for some other reason.

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Who is the Zodiac killer? - The truth is that, since then, no one has ever heard from the serial killer again. After the events, several theories were developed about the identity of the Zodiac.

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Theories about Zodiac's identity - In 2014, Gary L. Stewart stated that his stepfather Earl Van Best Jr. was the Zodiac killer. The conclusion was based on research he conducted for a period of 10 years.

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Conclusive evidence - Gary L. Stewart presented evidence that his stepfather could indeed be the killer. The portrait is similar to the one sketched by the police, but the most conclusive evidence was Earl Van Best Jr's confession in an audio recording, where he claims to be the Zodiac killer.

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Another suspect - On the other hand, Deborah Perez also said that her stepfather, who died of cancer in 1993, was in fact the Zodiac killer, given the similarities between the  police facial composite and her stepfather.

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Several suspects - Although police investigated close to 2,500 suspects, the case was never solved, not least because the technology of the day was not advanced enough to link a suspect to a crime.

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New research - However, a new documentary entitled 'The Zodiac Killer: Case Closed?' aired on 22 November 2017 brought forward new clues.

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Real identity? - Former Los Angeles homicide detective Sal LaBarbera and cold case expert Ken Mains, have discovered that there is enough evidence to prove that Bates was murdered by the Zodiac and believe they could point to Ross Sullivan as the prime suspect, a criminal who was arrested in 1968 for exhibiting strange behavior. If he's alive, Sullivan would now be 76 years old.

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Questions and answers - The case, which has puzzled detectives and police for decades, may be finally closed. But is this the true identity of the Zodiac killer? Or will there be more mysteries to decipher? What is certain is that the terrifying killer managed to frighten locals and create a culture of fear that lasts to this day.

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