John Gilbert Graham, known as "Jack," was born on January 23, 1932, in Denver, Colorado. He was born in the depths of the Great Depression, a time when financial hardship defined many American lives. His early years were shaped by instability. His father, William Graham, died of pneumonia in 1937, when Jack was just five. Due to financial constraints, his mother, Daisie King (née Walker), sent him to an orphanage.

Despite later finding financial success, Daisie did not reclaim her son from the orphanage. She remarried a third time to Earl King, who died shortly afterward, leaving her with an inheritance that helped her become a prosperous businesswoman. Still, she remained estranged from Jack until he was in his early twenties.

Their reunion in 1954 was far from heartfelt. Though Jack had reentered her life, their relationship was tense and riddled with conflict. Jack was known to harbor resentment toward Daisie, blaming her for his abandonment and upbringing. He was described by acquaintances as moody, manipulative, and selfish, with a shady record that included convictions for check forgery and illegal whiskey transport. He had also served 60 days in prison in Texas.

By the early 1950s, Graham had married Gloria Elson, with whom he had two children. Outwardly, they seemed like an average American family, but Jack's financial schemes told a different story. In 1955, a gas explosion destroyed Daisie’s restaurant under suspicious circumstances. Authorities believed it was arson, and Graham collected insurance money from it. There were also rumors that he had staged a train accident with his pickup truck for a fraudulent claim.

On November 1, 1955, United Airlines Flight 629 departed from Stapleton Airport in Denver, Colorado, headed for Portland, Oregon. Minutes after takeoff, the plane exploded in mid-air over farmland near Longmont. All 44 people aboard died in the blast, including crew and passengers. Among them was 54-year-old Daisie King—Jack Graham’s mother.

In the hours after the explosion, investigators combed through the charred wreckage of the Douglas DC-6B aircraft. Suspicion quickly grew when remnants of a suitcase were found embedded with traces of dynamite. The FBI determined that the bomb had been placed inside one of the passenger suitcases loaded in the forward baggage compartment.

Daisie King had been on her way to visit her daughter in Alaska. She had checked her bag that day with her son’s assistance. What no one knew at the time was that Jack had packed her luggage with a homemade dynamite time bomb. In a calculated move, he purchased five life insurance policies—totaling $37,500—at the airport just before her flight departed. These policies could be bought easily from vending machines at terminals, with no questions asked.

As investigators dug deeper, they uncovered a pattern. Jack had recently benefited from multiple insurance claims, including the suspicious restaurant explosion and a vehicle crash. His criminal history and strange inconsistencies in his alibi made him a person of interest. A search of his home uncovered bomb-making materials, and eventually, Graham confessed—claiming he did it for the money, though he also made conflicting statements about protecting his wife from FBI pressure.

Though he confessed, Graham later recanted. But the evidence against him was overwhelming. He had told prison doctors he didn’t care how many people were on board. “It could have been a thousand. When their time comes, there’s nothing they can do about it.” The chilling indifference shocked the public and made national headlines.

Because no federal law at the time explicitly made aircraft bombing a crime, prosecutors opted to charge Graham with the murder of a single person: his mother. The simplicity of the case helped ensure a swift trial.

In May 1956, Graham was found guilty of premeditated murder. While awaiting execution, he attempted suicide in his cell but survived. On January 11, 1957, he was executed in Colorado's gas chamber. His last words, reportedly spoken to the warden, were either a simple "Thanks, Warden," or the darker quote captured by TIME: “Everybody pays their way and takes their chances.”