In the late 1960s, northern California was terrorized by an unknown serial killer who went by the name of the Zodiac Killer. Throughout this killer's reign, he taunted the police along with the media, sending them on wild goose chases and making them waste time on cryptograms or ciphers. It is claimed that he killed 37 people, however, only 7 were truly confirmed to be him.

The first murders that were widely attributed to the Zodiac Killer were the murders of high school students Betty Lou Jensen and David Arthur Faraday. This occurred on December 20, 1968, on Lake Herman Road, which is just inside Benicia city limits. The couple was on a date, and it is believed that around 10:15 p.m. they pulled off onto what was considered lovers' lane.

It wasn't long after that their bodies were found by Stella Borges. The first death was Faraday. It appeared Jensen had exited the car first, but when Faraday was halfway out, the killer shot him in the head. As Jensen tried to flee, the killer then shot her in the back five times. While Faraday was found close to the car, the body of Jensen was found 28 feet from the vehicle.

The next murder was on July 4, 1969, of Darlene Ferrin and Michael Mageau. Similar to Jensen and Faraday, they had parked their car in Blue Rock Springs Park, only four miles from the previous murder. A car pulled up behind the couple and the driver got out with a flashlight and a gun. The killer shined the flashlight in Ferrin and Mageau's eyes and fired five times.

After walking away, the killer heard Mageau's moaning, so he returned to the car and shot them each twice before driving off. While Ferrin was pronounced dead at the hospital, Mageau did survive the attack despite being shot in the face, neck, and chest. Mageau was able to describe his attacker as a 26-to-30-year-old, 195-to-200-pound or possibly, even more, 5-foot-8-inch white male with short, light brown curly hair.

After the murders of Ferrin and Mageau, someone called the police station on July 5, 1969 claiming responsibility for both sets of murders. Shortly after on August 1, 1969, three letters written by the killer were given to three separate media sources. In these letters, there was one-third of a 408-symbol cryptogram which the killer claimed contained his identity.

The killer demanded they be printed on each paper's front page or he would "cruse around all weekend killing lone people in the night then move on to kill again until I end up with a dozen people over the weekend". The newspapers published these letters and cryptograms. On August 7, 1969, another letter arrived at newspaper stations in which the killer first refers to himself as the Zodiac.

This letter is in response to the Chief of Police asking for more proof that he really is the killer. In the letter, there were details about the murder that had not yet been released by the police. Shortly after this letter, someone decoded the killer's original cryptogram. It failed to reveal his true identity however it did reveal that he was apparently collecting slaves for his afterlife. The killer said that he would not give away his identity because it would slow down or stop his slave collection.

This continued until 1974 when the letters stopped. In the last letter, the killer discussed the movie "The Exorcist" and ended it by saying "Me = 37, SFPD = 0". While the police continued to search, the cryptogram consisting of 340 characters that the killer sent in 1969 remained unsolved until December of 2020. This cryptogram again failed to have the real killer's identity.

While many people have been accused to be The Zodiac Killer, the most serious accusation was towards Arthur Leigh Allen. This was disproven though when the DNA from Allen came back not matching that of the zodiac killer's, which was collected from the stamps on the letters. In 2004, the case was marked as inactive.

It was then reopened, and a team of over 40 cold case investigators started working on the case. The team identified the killer as Gary Francis Poste, who died in 2018. There has been overwhelming evidence that connects Poste to all the killings. Some of the newfound evidence are murders that now seem to be connected to the Zodiac Killer that were also connected to Allen. Many people have stepped forward and started to reveal new information that further connects Allen and makes him seem more and more likely to be the Zodiac Killer.