When commercial airliners crash, there’s usually an easy explanation to help investigators. The accident is, more often than not, found to be the result of either a malfunctioning piece of equipment or an error by a pilot.

When John Graham’s mother and 39 other passengers were mysteriously killed in a plane crash on November 1, 1955, however, no one could lend any explanation as to what had caused the tragedy to take place.

When the FBI later looked through John’s mother’s luggage, however, they made a discovery that shook them to their core…

On November 1, 1955, approximately 11 minutes after United Airlines Flight 629 left from Denver, Colorado, the aircraft suddenly burst into flames. The explosion resulted in fiery debris falling from the sky onto the earth’s surface below.

Pinsdaddy

The plane had made several other trips that day, all without any issue or cause for concern. Departing from La Guardia Airport in New York City, it made a brief pit stop in Chicago, Illinois, before making its way to Denver’s Stapleton International Airport.

Pinsdaddy

Once the plane arrived to Denver at 6:11 p.m., it was refused on the airport tarmac and a new flight crew got on board. The plane took off once again, at 6:52 p.m., and headed to Portland, Oregon. Its final destination would be Seattle, Washington, though it tragically never made it to either city—and the reason why was horrifying…

Pinsdaddy

Four minutes into the flight, the pilot of the aircraft sent a message to the airport control that everything was going as planned. Then, just seven short minutes later at 7:03 p.m., things took a turn. The air traffic controllers at the Stapleton Airport saw a pair of mysterious lights flash in the night sky.

Pinsdaddy

Somewhere between 30 seconds to one minute later, a series of people saw those same two lights plummet out of the night sky. Moments later, they witnessed a massive flash strike near the surface of the ground. As air traffic control sent messages out to all airborne flights, it became clear that Flight 629 had crashed.

Pinsdaddy

Reports began to flood in about various debris falling from the skies above in the town of Longmont, some 30 miles away from the airport. Sadly, by the time emergency responders arrived at the scene, there were no survivors. What happened?

Pinsdaddy

In total, five crew members and 39 passengers died. The eldest victim, Lela McLain, was 81 years old, while the youngest was a newborn boy who was just 13 months old. As the news broke, people all across the United States were beside themselves, and authorities began to investigate what had gone wrong.

Pinsdaddy

Once the investigation began, authorities made some quick discoveries. In addition to the overwhelming scent of explosive materials at the crash shite, the Civil Aeronautics Board found that the aircraft had blown up with a massive force. They knew that no actual part of the aircraft malfunctioning could’ve possibly been responsible for such a blast.

Pins daddy

The investigation quickly turned from one of technical malfunction to that of a planned attack. They began to assume that someone had smuggled a bomb on board. Still, they had no idea why anyone would’ve done such a thing.

Pinsdaddy

Nevertheless, authorities continued to investigate the debris from the crash. Soon, they learned more that made them realize that it was a planned attack. On four pieces of sheet metal, they discovered traces of chemicals used in dynamite.

Pinsdaddy

With that knowledge, investigators were forced to call in the FBI, which was also convinced that someone had placed a bomb on Flight 629 that fateful night. The search for potential suspects in the blast began with the deceased passengers themselves.

Pinsdaddy

More specifically, the FBI turned their attention to those passengers from the Denver, Colorado, area. While searching through the passengers’ backgrounds, they found that a number of those on the flight had recently taken out life insurance policies.

Pinsdaddy

The investigation soon narrowed its focus on one suspect: 53-year-old Daisie King of Denver. She’d apparently been headed to Alaska to visit her daughter, but when investigators sifted through her luggage, they found an unexpected detail about her…

Pinsdaddy

Inside of Daisie’s handbag, the FBI investigators found several news clippings about Daisie’s son from her second marriage—and local criminal—John Gilbert Graham. She’d given birth to him in 1932, but when she fell on hard times and his father passed away, she was forced to turn him over to an orphanage.

Pinsdaddy

When Daisie’s third marriage ended in her spouse’s death, she earned a hefty inheritance. After that, she used some of the money to start a thriving business, the Crown-A Drive-In diner. Still, she never attempted to locate her son until some 22 odd years later. In 1954, they were rumored to have met up and reconciled completely. That wasn’t all they’d done, however…

Pinsdaddy

As the FBI investigators eventually learned, Daisie named John the beneficiary to her life insurance policy. Additionally, her Crown-A Drive-In diner had recently been damaged in an explosion, and she’d received a hefty insurance settlement.

Pinsdaddy

The FBI soon turned their search focus to John’s home. In his garage, they discovered bomb-building supplies similar to those they suspected were used in the bombing of Flight 629, as well as a number of life insurance policies.

PinsDaddy

It wasn’t long before John’s alibi unraveled before his very eyes. Initially, John claimed his mother had packed her own luggage, though his wife, Gloria, confessed that she’d seen him packing her bags for her. Daisie had no idea that her son had been planning to kill her.

PinsDaddy

Under mounting evidence, John eventually confessed to the crime, stating that he’d placed dynamite in the unsuspecting Daisie’s suitcase. Additionally, the FBI was disturbed to find he’d showed no remorse for either his own mother’s death or the other innocent passengers on board Flight 629.

PinsDaddy

Perhaps most shockingly of all, placing a bomb on an aircraft was not considered breaking the law at that time. Nevertheless, John was convicted of his mother’s murder and executed on January 11, 1957. Eight months later, President Dwight Eisenhower signed a bill making it illegal to attack commercial airliners.

PinsDaddy

How tragic. Daisie thought she’d reconciled her differences with her son, but she was wrong.

Share this tragic story with your friends below!