The biggest unsolved cold cases still open today include the Zodiac Killer murders in Northern California, the killing of six-year-old JonBenét Ramsey in Boulder, Colorado, and the Villisca axe murders of 1912, investigations spanning 57 to 114 years without a single conviction. These are not obscure files gathering dust in a basement. They involve multiple […]
The biggest unsolved cold cases still open today include the Zodiac Killer murders in Northern California, the killing of six-year-old JonBenét Ramsey in Boulder, Colorado, and the Villisca axe murders of 1912, investigations spanning 57 to 114 years without a single conviction.
These are not obscure files gathering dust in a basement. They involve multiple victims, massive public attention, and in some cases suspects police have named and then failed to charge. We covered six of the most famous cases that refuse to fade in our earlier roundup of famous cold cases that are still unsolvedThis time the angle is different: why these investigations stalled, and what it says about how police handle evidence.
Key Facts
- The Zodiac Killer attacked at least seven people in Northern California between December 1968 and October 1969; five died. No one has ever been charged.
- JonBenét Ramsey was found dead in her family’s Boulder, Colorado home on December 26, 1996. A grand jury voted to indict her parents in 1999. No arrest has followed.
- The Villisca axe murders killed eight people in Villisca, Iowa, on June 10, 1912. The case has now been unsolved for 114 years.
- D. B. Cooper hijacked a Northwest Orient plane on November 24, 1971, took $200,000, and vanished. The FBI closed its active investigation in July 2016.
- The Somerton Man, found dead on an Adelaide beach on December 1, 1948, was finally identified in 2022 as Carl Webb, using DNA, proof old cases can crack.
What Are the Biggest Unsolved Cold Cases Still Open?
The biggest unsolved cold cases are investigations with multiple victims, decades of police work, and no conviction. Four stand out for their scale and the questions they leave open.
The Zodiac Killer: 57 Years, Zero Arrests
Between December 20, 1968, and October 11, 1969, a gunman attacked seven people across Benicia, Vallejo, Napa County, and San Francisco. Five died, including cab driver Paul Stine, shot in the Presidio Heights neighborhood. The killer mailed letters and ciphers to Bay Area newspapers. One, the 408-symbol cipher, was cracked within weeks in 1969. The 340-symbol cipher sent in November 1969 stayed unsolved for 51 years until amateur codebreakers David Oranchak, Sam Blake, and Jarl Van Eycke broke it in December 2020, a solution the FBI confirmed.
The case remains open across multiple jurisdictions. The main suspect police pursued, Arthur Leigh Allen of Vallejo, died in August 1992 without ever being charged. His DNA, according to reporting over the years, did not match the evidence.
JonBenét Ramsey: A Grand Jury Vote, Then Silence
JonBenét Ramsey, six years old, was reported missing by her mother Patsy Ramsey on the morning of December 26, 1996, along with a ransom note demanding $118,000. Her body was found that afternoon in the basement of the Boulder home; she had been strangled. The crime scene, by the admission of later reviews, was compromised: friends and family moved through the house for hours before police secured it.
Here is the part that should anger every reader. In 1999, a Boulder County grand jury voted to indict John and Patsy Ramsey on charges of child abuse resulting in death. Then-District Attorney Alex Hunter declined to sign the indictment, saying the evidence was insufficient. The vote stayed secret until 2013. In 2008, then-District Attorney Mary Lacy cleared the family based on touch DNA. Nearly 30 years on, no one has been charged. According to the Boulder Police Department, detectives continue working with the Colorado Bureau of Investigation and the FBI on new DNA testing of the evidence.
The Villisca Axe Murders: Eight Dead, 114 Years, No Answer
On June 10, 1912, someone killed eight people in a small white house in Villisca, Iowa: Josiah and Sarah Moore, their four children, and two visiting girls, Lena and Ina Stillinger. All were struck with an axe as they slept. The only man ever tried, traveling minister George Kelly, faced two juries in 1917; the first deadlocked, the second acquitted him. No one else was ever charged.
D. B. Cooper: The Case the FBI Shelved
On November 24, 1971, a man calling himself Dan Cooper hijacked Northwest Orient Flight 305 from Portland to Seattle, extorted $200,000, and jumped from the rear stairs somewhere over the Pacific Northwest. In February 1980, a boy found $5,800 of the ransom cash, matching serial numbers, on a Columbia River beach near Vancouver, Washington. The rest never surfaced. In July 2016, the FBI closed the active investigation, saying resources were needed elsewhere. The evidence file, the agency said, remains preserved.
Why Do the Biggest Unsolved Cold Cases Stay Unsolved?
The honest answer is that most of these cases were damaged in their first days, and DNA has been slow to fix it.
- Contaminated scenes. In Boulder, hours passed before the Ramsey house was locked down. That destroys touch DNA before it is ever collected.
- Splintered jurisdictions. The Zodiac struck in at least four police jurisdictions in 1969, an era before shared databases.
- Shelved files. The FBI closed the Cooper case in 2016, not because of a breakthrough but because of budget priorities.
- Destroyed evidence. Across US jurisdictions, evidence from the 1960s and 1970s was routinely discarded after decades in storage.
A cold case, put simply, is a criminal investigation that police have stopped actively working because all leads are exhausted. The label describes the paperwork, not the crime.
| Case | Date | Victims | Status as of October 2026 |
|---|---|---|---|
| Zodiac Killer | December 1968 to October 1969 | 7 attacked, 5 killed | Open, no suspect charged |
| JonBenét Ramsey | December 26, 1996 | 1 | Open, DNA retesting underway |
| Villisca axe murders | June 10, 1912 | 8 killed | Unsolved, 114 years |
| D. B. Cooper | November 24, 1971 | 0 (theft, $200,000) | Active case closed by FBI in 2016 |
| Somerton Man | December 1, 1948 | 1 | Identified in 2022 as Carl Webb |
Can DNA and Genealogy Finally Crack the Biggest Unsolved Cold Cases?
Yes, and the proof is already on the record. The Somerton Man, found dead on Somerton Beach in Adelaide, Australia, on December 1, 1948, with a scrap reading “Tamám Shud” sewn into his trousers, was identified in 2022 as Carl Webb, a 43-year-old instrument maker from Melbourne, after researchers Derek Abbott and Colleen Fitzpatrick traced living relatives and confirmed the match through DNA. South Australian Police accepted the identification, 74 years after the body was found.
Genetic genealogy has done the same in the United States. Joseph James DeAngelo, the Golden State Killer, was arrested on April 24, 2018, after investigators matched crime scene DNA to relatives on a public genealogy database. He pleaded guilty in 2020. If a 74-year-old Australian mystery and a 40-year-old California killing spree can be cracked this way, the Ramsey and Zodiac evidence sitting in storage is the obvious next target. The obstacle is not science. It is money, chain-of-custody paperwork, and departments willing to spend both.
Fifty-seven years after that letter arrived, the man who wrote it has still never stood trial.
FAQ
What is the oldest unsolved cold case in the United States?
The Villisca axe murders of June 10, 1912, in Villisca, Iowa, are among the oldest famous unsolved cases in the country. Eight people were killed with an axe, and no one was ever convicted.
Has the Zodiac Killer ever been identified?
No. The Zodiac killed five confirmed victims in Northern California in 1968 and 1969, and no suspect has ever been charged. The main police suspect, Arthur Leigh Allen, died in 1992 without charge.
Will the JonBenét Ramsey case ever be solved?
The Boulder Police Department says it is still working the case with the Colorado Bureau of Investigation and the FBI, including new DNA testing. No arrest has been made in the nearly 30 years since December 26, 1996.
Why did the FBI close the D. B. Cooper case?
The FBI closed the active investigation in July 2016, citing the need to focus resources on other work, while keeping the evidence file preserved. No credible claim of identifying Cooper has been confirmed since.
How has DNA changed cold case investigations?
Genetic genealogy, matching crime scene DNA to relatives in public databases, solved the Golden State Killer case in 2018 and identified the Somerton Man in 2022. It works only when original DNA evidence was properly collected and stored.
Sources: FBI — D. B. Cooper – Boulder Police Department – FBI — Zodiac cipher statement – Villisca Axe Murder House historical recordUpdated: October 23, 2026.
