3 Unsolved Cold Cases That Still Trouble the FBI

D.B. Cooper: The Hijacker Who Vanished Into Thin Air

On a stormy November evening in 1971, a man calling himself Dan Cooper walked onto a Boeing 727 and changed aviation history forever. The hijacker told authorities he had a bomb and demanded $200,000 and four parachutes, then jumped from the plane into the Pacific Northwest wilderness, never to be seen again. The FBI closed its investigation into the 1971 plane hijacking back in 2016, yet the case refuses to stay buried.

Let’s be real, most cold cases fade with time. This one got hotter. The recent discovery of a modified parachute on the property of a former suspect has reignited national attention. After watching investigative videos, FBI agents contacted the family and contacted the family in North Carolina, where they took the harness and parachute into evidence along with a skydiving logbook. The suspect? Richard Floyd McCoy II, a man who pulled off an almost identical hijacking just months later.

Rick McCoy reportedly provided a DNA sample, with agents mentioning possible exhumation of his father’s body. The thing is, McCoy’s children stayed silent for decades, believing law enforcement could charge their mother if they spoke up. Their report states they stayed quiet for decades until their mother died. The FBI would not confirm or deny that it is actively reinvestigating the Cooper case, leaving the public in a familiar limbo.

Former FBI agent Larry Carr, who retired from the Bureau in 2022, believes the agency may be conducting testing discreetly, adding that even though the FBI announced the case closed in 2016, it may never have been. The parachute rig found is described as being unique. Honestly, after more than fifty years of dead ends and wild theories, could a piece of fabric finally crack America’s only unsolved hijacking?

The Zodiac Killer: A Serial Murderer Still Anonymous

In May 2023, the FBI confirmed to Newsweek that the killer’s identity remains officially unknown. That single sentence captures the haunting reality of one of the most infamous unsolved cases in American criminal history. Between 1968 and the early 1970s, a masked killer terrorized Northern California, taunting police with cryptic letters and ciphers. Official investigations link the Zodiac to five murders and two attempted murders across four different locations.

The killer became legendary not just for the brutality of the crimes but for the psychological torment inflicted on investigators and the public. In a stunning international breakthrough in 2020, a team of civilian code-breakers finally solved the infamous 340 Cipher, revealing a chilling, self-aggrandizing message. Still, other codes remain unsolved, meaning vital clues could still be hidden in plain sight.

Over the course of their decades-long investigation, police have only ever publicly identified one suspect in the Zodiac Killer case, Arthur Leigh Allen, but they never found enough evidence to charge him. Allen died in 1992, taking whatever secrets he had to the grave. In the early 2000s, DNA evidence extracted from saliva on the stamps and envelopes of the Zodiac’s letters was compared to Allen’s samples and reportedly excluded him as the source. Yet recent investigations have presented testimony from those who knew Allen, raising fresh suspicions.

As of 2025, law enforcement was actively using forensic genetic genealogy and advanced DNA technology to analyze evidence from his taunting letters and cryptic ciphers. Despite multiple independent groups claiming to have identified the killer over the years, authorities remain cautious. An FBI statement from 2021 confirmed that the Zodiac Killer case remains open, with no new information to share, and no one has been charged with the Zodiac’s crimes as of October 2024. The question lingers: Will modern science finally unmask a ghost from the sixties?

Jimmy Hoffa: The Union Boss Who Disappeared Without a Trace

It has been 50 years since the disappearance of James “Jimmy” Hoffa, one of the most well-known missing person investigations in FBI history. On July 30, 1975, the powerful Teamsters president vanished from a suburban Detroit restaurant parking lot. He was supposed to be meeting with reputed mob figures. He never came home.

Though Hoffa was declared legally dead by a Michigan probate court in 1982, officially, the Detroit branch of the FBI says the case remains open. The theories about what happened are as colorful as they are grim. People have claimed his body lies under Giants Stadium in New Jersey, beneath a Detroit freeway, even dissolved in an acid vat. A 2022 claim pointed to a former New Jersey landfill, but no evidence of Hoffa has been found there.

An independent investigative team known as The Case Breakers has asked the FBI to begin searching under a parking lot next to the Brewers’ stadium, claiming clues point to him being under the spot where third base was located. The team says they received a clue written on an Ace of Spades playing card from a former Chicago cop. A 93-year-old New Jersey attorney says a witness has recently come forward and told him exactly where Hoffa’s body was dumped, claiming a man named Jeff saw men in two cars pull up on property near the Pulaski Skyway in April 2025.

Here’s the thing: The Hoffa investigation remains active, and the FBI continues to urge anyone with information to come forward. Nearly half a century of tips, excavations, and speculation have yielded nothing concrete. The mystery endures not because investigators lack theories but because physical evidence refuses to surface. Nearly 346,000 cases of homicide and non-negligent manslaughter went unsolved from 1965 to 2023, according to the FBI’s Uniform Crime Report data studied by The Murder Accountability Project. Hoffa’s case remains one of the most notorious among them.