Some crimes are solved in days. Others stay open for decades, passed from one detective to the next. These famous unsolved cold cases have fascinated the public for generations, and all of them remain officially open today.

What Is a Cold Case?

A cold case is a criminal investigation that has gone inactive because the leads have run dry. It is not closed, though. Many police departments keep these files alive, and new DNA tools are reopening them more often than before.

1. The Zodiac Killer (California, 1968–1969)

A killer calling himself “Zodiac” attacked couples in Northern California and taunted police and newspapers with coded letters. He has been linked to at least five murders.

Why it is still unsolved: Nobody has ever been charged. One cipher was cracked in 2020, but another still has not been solved. In 2026, an independent researcher claimed to have identified the killer, but these claims have not been confirmed by authorities, and the case remains officially open.

2. The Black Dahlia (Los Angeles, 1947)

In January 1947, 22-year-old Elizabeth Short was found murdered in a vacant lot in Los Angeles. The press named her the “Black Dahlia,” and the case turned into a media frenzy.

Why it is still unsolved: Detectives followed hundreds of leads and dealt with many false confessions, but no one was ever charged. Nearly eight decades later, there are no living witnesses to interview, which makes it one of the hardest cases to crack.

3. D.B. Cooper (United States, 1971)

A man using the name “Dan Cooper” hijacked a Northwest Orient flight, collected a $200,000 ransom, and parachuted into the night over the Pacific Northwest. He was never seen again.

Why it is still unsolved: It remains the only unsolved airplane hijacking in US commercial aviation history. Nobody knows whether he survived the jump.

4. The Isabella Stewart Gardner Museum Heist (Boston, 1990)

On St. Patrick’s Day 1990, two thieves posing as police officers stole 13 artworks, including works by Vermeer and Rembrandt. The loss is estimated at around $300 million.

Why it is still unsolved: Despite a multimillion-dollar reward and a long investigation, the world’s biggest art heist has not been cracked, and the paintings have not been recovered.

5. The Chicago Tylenol Murders (1982)

In 1982, several people in the Chicago area died after taking Tylenol capsules that had been tampered with. The case shook the country.

Why it is still unsolved: No one was ever convicted of the poisonings. The case did change the world, though: it led to tamper-proof packaging on everyday medicines.

6. Jack the Ripper (London, 1888)

The Whitechapel murders of 1888 created the template for the modern serial killer story, complete with press frenzy and anonymous letters.

Why it is still unsolved: More than 130 years later, the killer has never been officially identified. Many theories and claims have appeared, but none has been proven.

Why Do Cold Cases Stay Unsolved?

  • Evidence gets lost or degraded over time.
  • Witnesses die or forget.
  • Old investigations lacked forensic tools we have today.
  • Mistakes and tunnel vision can send detectives in the wrong direction.
  • The suspect may be dead, so there is no one left to prosecute.

Can DNA Still Solve These Cases?

Sometimes, yes. Investigative genetic genealogy, which compares crime-scene DNA with family trees in public databases, has cracked many old cases. In 2026 alone, DNA linked serial killer Ted Bundy to the 1974 murder of 17-year-old Laura Ann Aime, and a Texas judge declared four men innocent in the 1991 Austin yogurt shop murders after DNA identified the real killer.

For the oldest famous cases, though, the problem is that physical evidence is limited or gone. That is why some mysteries may never get a final answer.

Final Thoughts

These cases stay in our minds not only because of the crimes themselves, but because the answers are still missing. Every new DNA breakthrough brings hope that one day one of them will finally be closed.

FAQ

What is the most famous unsolved case in the world?
Jack the Ripper and the Zodiac Killer are usually named as the most famous, depending on the country.

Is the Zodiac Killer case still open?
Yes. Claims about a suspect have appeared, but the case is officially unsolved.

Is the D.B. Cooper case still open?
It remains the FBI’s only unsolved airplane hijacking case.

Can cold cases really be solved after decades?
Yes, especially with DNA and genetic genealogy, although very old cases are much harder.