The most notorious serial killer in living memory may finally be unmasked thanks to modern-day technology and clever detective work.
Investigators are now planning to use DNA found at one of the Zodiac Killer's suspected crime scenes to reveal the murderer's true face.
'It's probably the greatest American unsolved serial killing case,' cold case detective Ken Mains told Fox News. 'I'm very confident it can be solved.'
Mains believes the killer's DNA has been obtained from the scene of the grisly murder of 18-year-old student Cheri Jo Bates, reports Daily Mail.
Bates was attacked, stabbed to death and nearly beheaded on October 30, 1966, while leaving the library at Riverside Community College.
"During the examination of Bates' clothing, I discovered, without a doubt, two bloody handprints at the bottom of her pants," Mains said.
"We have touch DNA from those handprints," added the former FBI task force member and Marine Corps vet, who stars in HISTORY's new documentary series The Hunt For The Zodiac Killer.
He believes that the killer was one of two men: Ross Sullivan and Lawrence Kane.
Sullivan worked at the library outside which Bates was killed, and bore a striking resemblance to police sketches of the killer.
He also wore military-style boots with prints similar to those found at the murder scene, and was interviewed by police in connection with Bates' death - though never charged.
He had an interest in cryptography, which means he may have been capable of creating the elaborate coded letters sent to newspapers by the killer.
And he was arrested in 1968, the year of the first Zodiac killings, for "bizarre behavior" in Santa Barbara - not far from where the murders took place.
Sullivan's current whereabouts are unknown; if he is alive, he will be 76 years old.
Kane, meanwhile, was a cryptographer for the Navy - again suggesting that he may have been able to write the complex letters - who died in 2010.
Only seven attacks were confirmed by police as being those of the Zodiac Killer - and Bates' is not one of them.
However, six months after her death, her father, the local police and the Press-Enterprise all received letters signed 'Z' with the message "She had to die there will be more".
And after a 1970 report linked Bates' murder to the Zodiac Killer, he wrote to the LA Times claiming that he had murdered Bates and others in the Riverside area.
Riverside police maintain that her death was not a Zodiac case, and say that at most the real killer was trying to falsely claim credit for her killing.
Nevertheless, Mains is hopeful that he and his compatriots on the show - LA homicide detective Sal LaBarbera and code-breaker Kevin Knight - will crack the case.
One of the tools they have in their arsenal is CARMEL, a supercomputer that is being used to analyze and decode the elaborate cryptograms in Zodiac's letters.
The team claim that it has already solved a substantial portion of Z340, the astoundingly complex 340-character cipher mailed on November 8, 1969, to the San Francisco Chronicle.
The Zodiac killer's victims
Although the Zodiac Killer claimed to have killed as many as 37 people in his letters to local newspapers, police have only linked five murders - and two other injuries - to him.
On December 20, 1968, David Arthur Faraday, 17, and Betty Lou Jensen, 16, were on their first date when they pulled over into a lovers' lane on Lake Herman Road in Benicia.
There, they were forced from the car by a killer and Faraday was shot in the head. Jensen began to run away but was shot multiple times in the back.
On July 4, 1969, Michael Renault Mageau, 19, and Darlene Elizabeth Ferrin, 22, were in the parking lot of Blue Rock Springs Park in Vallejo - 4 miles from the first crime scene - when they were shot 'to pieces', according to the investigator.
But while Ferrin was pronounced dead on arrival, Mageau survived being shot in the face, neck and chest.
On September 27, 1969, Bryan Calvin Hartnell, 20, and Cecelia Ann Shepard, 22, were having a picnic at Lake Berryessa in Napa County when they were approached by a hooded man who bound and stabbed them. Hartnell survived eight stab wounds to his back, but Shepard died two days later.
On October 11, 1969, cab driver Paul Lee Stine, 29, picked up a passenger and drove him to Presidio Heights - where he was shot in the back of the head and robbed.
The killer also ripped part of Stine's shirt, which he later sent with a letter to a local newspaper.
Four other victims and one other escapee have been connected to the Zodiac Killer, but none have been confirmed.