Ten years ago, police have tried to extract DNA from evidence and old letters but with no success.
"I mean, they go from California to OR to get my dad's DNA? I found that much of it was not packaged correctly", he said.
However, the killer has seemingly claimed more than 30 killings and sent a series of freaky and detailed letters to news organisations that included cryptograms, in which he called himself "Zodiac".
During the Zodiac's violent killing spree, seven people were attacked, five of whom died, in Benicia, Vallejo, Lake Berryessa and San Francisco.
A former California homicide detective recently declared that it might be possible to establish the identity of the infamous Zodiac killer by taking advantage of cutting-edge DNA sampling techniques.
Joseph James DeAngelo, 72, has been arrested by police investigating the Golden State Killer deaths.
Comparison of DNA might help to find the famous serial killer Zodiac in perennial frozen, as happened in the history of California "Golden state Killer". The last confirmed victim was cab driver Paul Stine.More news: Manchester City's Leroy Sane: Everyone wants to beat the champions
On the other hand, Dr. Miller says, "If it were kept in a box in a warehouse subjected to heat and cold cycles, you probably wouldn't get anything off it after 40 years".
DNA from a crime scene was matched to genetic material from a relative who was registered on genealogy sites, and authorities later obtained a discarded sample of DeAngelo's DNA. "Just copy what was done with the Golden State Killer".
"In accordance with our ethical and professional standards, we will refrain from discussion of the facts of the case or our position on any matter while the case and investigation is ongoing", an office representative told Newsweek. My 4-year-old daughter was laying alongside the bed. Others have raised privacy concerns about police use of a non-governmental DNA database to identify unwitting relatives of participants.
Carlisle said physical evidence from that attack, including a auto door and a blanket, were re-processed for DNA evidence in about 2010, but again the samples were found to be mixed and only a partial profile was obtained. Matches from distant family members and the reconstruction of a family tree led police to DeAngelo.
"In the present case, obtaining the defendant's major case prints and his DNA sample does not require him to speak or say even a word", deputy district attorneys Thienvu Ho and Amy Holliday wrote in a filing obtained by the Bee.
"There's a formula to follow", Voigt said. He said the arrest in the East Area Rapist case instantly made him think of the man who terrorized the Bay Area so many years ago.