"It’s definitely possible," said forensic scientist Ruth E. Ballard of California State University, Sacramento. "If they didn’t steam the stamp off and it was stored in a cool dry place, maybe there’s sufficient DNA left." 
 
 The April 25 arrest of 72-year-old Joseph James DeAngelo in the Golden State Killer case has renewed interest in the state's Zodiac serial killer saga, which was the subject of a 2007 movie "Zodiac." 
 
 But detectives say the timing is pure coincidence. 
 
 In a bid similar to the one undertaken by Golden State Killer investigators, police in Vallejo, California, sent two letters connected to the suspect to a private lab months ago, Detective Terry Poyser said. He added that the results of the newest DNA testing were expected soon and that detectives hope to submit them to a familial DNA service. 
 
 Investigators in the Golden State Killer case uploaded DNA to an open-source genealogical website, where they claim to have found a partial match to DeAngelo's distant relative. 
 
 Police who collared the former police officer said they had to produce a family tree dating back several generations before they zeroed in on DeAngelo, suspected in at least 12 murders and 50 rapes between 1976 and 1986. 
 
 Ballard is optimistic about the odds of catching the Zodiac Killer. She said the science of extracting DNA from everyday items continues to accelerate. "Our power of discrimination has gone through the roof," she said. 
 
 Gary Harmor, director of a private lab known as the Serological Research Institute, said he's concerned the letters are too old to produce usable markers. 
 
 "I have worked with DNA from the 1960s and '70s at my lab," he said. "It’s hard to get enough that hasn’t degraded to get a profile from it." 
 
 Experts say another question is whether or not the evidence in the Zodiac file was stored in a cool, dry place or in a freezer. Because advances in DNA technology didn't start to change investigative protocols until the 1980s, the samples kept by Zodiac detectives would have had time to degenerate and take on bacteria. 

 Investigators searching for the Zodiac Killer have submitted evidence to a private DNA lab in the hopes of obtaining a genetic profile of one of California's most elusive criminals — then tracking him down using the same kind of family-tree tracing recently used in the East Area Rapist case. 
 
 Vallejo police Detective Terry Poyser, who has worked the Zodiac case for four years, said his agency has submitted two envelopes that contained letters from the Zodiac Killer for a type of advanced DNA analysis that previously had not been available in the case. 
 
 Poyser declined to identify the lab, but said it would attempt to obtain a full DNA profile from saliva on the envelope flap and stamps. He said he expected to have results back from the lab as soon as in the next few weeks, and almost certainly by summer. 
 
 "They were confident they would be able to get something off it," Poyser said. 
 
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 He said the envelopes had been sent to the lab a few months ago, before Joseph DeAngelo, who is suspected of being the East Area Rapist, was caught after investigators used a DNA profile run though an open-source database. Poyser said he hoped the same approach could be used if a complete profile of the Zodiac is obtained. 
 
 "If we get a good profile, then you start tracking back," Poyser said. "It really comes down to DNA. Without it, you have nothing. It's a 50-years-old case." 
 
 The use of public genealogy sites to track criminal DNA is relatively new. Prior to the case of the East Area Rapist, also known as the Golden State Killer, most investigations were limited to running DNA samples through state and federal databases that largely only contain DNA from convicted felons. 
 
 To be successful, those searches required the DNA belong to someone previously convicted, or to a close relative who also was a felon and therefore in the database. 
 
 In the East Area Rapist case, investigators have said they uploaded a genetic profile into an open source DNA database used by amateur genealogists searching for relatives, providing a much wider pool of potential matches. 
 
 Poyser said Vallejo police plan to do the same if a Zodiac sample is obtained. "We are having (the evidence) retested, and then we will go the routes we can," he said. 
 
 SHARE COPY LINK With the exception of identical twins, each person has a unique DNA profile. This makes DNA matching a powerful tool for finding and convicting the perpetrator of a crime. 
 
 The Zodiac Killer roamed Northern California from December 1968 through October 1969, but was never caught despite at least one close run-in with police. He is known to have attacked seven victims — in Benicia, Vallejo, Lake Berryessa and San Francisco — killing five and leaving two survivors. However, the Zodiac claimed responsibility for many more deaths in letters, often signed with a symbol of a cross over a circle. 
 
 
 
 
 
 Betty Lou Jensen and David Faraday were the first victims, on Dec. 20, 1968. The two high school students were shot on Lake Herman Road in Benicia, close to Vallejo. 
 
 A little more than six months later, the Zodiac struck again just a few miles from the first attack. On July 4, 1969, he shot Darlene Ferrin and Michael Mageau in Blue Rock Springs Park in Vallejo. Ferrin died, but Mageau survived. 
 
 The Zodiac killed two more times. At Lake Berryessa in Napa County, he attacked a young couple in September 1969. In that incident, he killed Cecelia Shepard, but her companion, Bryan Hartnell, survived. Two weeks later, the Zodiac shot San Francisco cab driver Paul Stine in the Presidio Heights neighborhood. 
 
 Vallejo became the lead agency in the case because of the Lake Herman Road killings and the Ferrin killing. When the Zodiac sent letters to Bay Area newspapers, they were forwarded to Vallejo police, Poyser said. 
 
 "That was our case at the time," he said. "(San Francisco) hadn't had the homicide of the cab driver yet." 
 
 The department has three letters and two envelopes from the Zodiac, Poyser said. The envelopes each have a double stamp, which Poyser said was a trademark of the Zodiac. They originally were sent to the San Francisco Chronicle and the San Francisco Examiner, he said. The third letter was sent to the Vallejo Times-Herald, but does not have an envelope with it, he said. 
 
 San Francisco police, who have been working on the case collaboratively with Vallejo, also have cards and ciphers sent by the Zodiac, he said. 
 
 Poyser said he believes the Zodiac Killer is no longer alive. Arthur Leigh Allen, a former elementary school teacher and convicted child molester who lived in Vallejo, long was considered a top suspect. Allen died in 1992 at the age of 58, according to media reports. 
 
 "Our Vallejo suspect is probably still the best lead," Poyser said of Allen. "There are probably 30 different circumstantial things that point to him. ... He was extremely intelligent but a deviant dude." 
 
 Allen largely was cleared as a suspect in 2002, when investigators obtained a partial DNA sample from the envelopes that didn't match his. Poyser said that DNA profile only had a few markers on it, less than half of the genetic points needed to definitively clear or identify a suspect. 
 
 Poyser said that DNA sample was hampered because technology didn't exist at the time to separate the glue used on the stamps and envelopes from the genetic material. However, science now has advanced to allow a clean grab of the DNA. 
 
 Poyser also said Allen was known to have asked other people to lick stamps and envelopes for him, claiming he didn't like the taste of the glue. "One of his friends actually said he did it for him, and we've had a couple people who lived in the neighborhood at the time say they did it as children," he said. 
 
 Poyser said if a clean DNA sample is obtained, police might ask those who licked materials for Allen to submit DNA swabs. If they matched the Zodiac profile, it would provide another link to Allen, he said. 
 
 Even if Allen doesn't prove to be the Zodiac, Poyser said he believes it was someone familiar with Vallejo, and perhaps with a law enforcement or military background. 
 
 He pointed out that the first four victims all were shot in rural areas likely only known to locals. He also said that Ferrin, the 22-year-old woman shot and killed in Blue Rock Springs Park, may have been known to the killer. She was a waitress in a Vallejo restaurant and, though married, was dating at least one police officer, a possible link to the Zodiac, Poyser said. 
 
 Poyser, who plans on retiring next year after 25 years of police work, said he thinks a resolution to the case is possible. 
 
 "People need to know that the agencies involved in this — Napa, Vallejo and San Francisco — have been cooperating with each other for quite some time, and everybody is committed to closing it out."
– First, the Golden State Killer—now the Zodiac Killer? With DNA evidence possibly pointing to the former, police say the same method could help identify the long-sought Zodiac Killer, NBC News reports. Police in Vallejo, Calif., say they sent two envelopes from the Zodiac Killer to a private lab for a new kind of DNA analysis months ago. Any clear genetic profile will be given to a family-tree DNA service like the one used in the Golden State Killer case. But can DNA from envelopes and stamps dating back nearly 50 years still be used? "It's definitely possible," says a forensic scientist. "If they didn’t steam the stamp off and it was stored in a cool dry place, maybe there’s sufficient DNA left." Vallejo police Detective Terry Poyser, who's had the case for four years, tells the Sacramento Bee that people at the lab "were confident they would be able to get something off it." In a surprise twist, lead suspect Arthur Leigh Allen—an ex-school teacher and known child molester who died in 1992—was cleared in 2002 when an incomplete DNA sample from the envelopes didn't produce a match. Modern DNA technology should get a better sample, although Allen was known to get friends and neighbors to lick envelopes for him, so police may ask those people to submit samples. "There are probably 30 different circumstantial things that point to [Allen]," says Poyser. "He was extremely intelligent but a deviant dude."