At 7:03 pm on November 1, 1955, a DC-6B (United Airlines Flight 629) crashed near Longmont, Colorado. The Civil Aeronautics Board and the FBI carried out a comprehensive recovery effort, and eventually pieced together most of the airplane. The tail had severed off cleanly, and when engineers from United and the manufacturer, Douglas Aircraft Corp., offered no viable explanation, the FBI considered it an act of sabotage.
Exhaustive interviews with family, neighbors, and business associates of the passengers led the FBI to focus on Jack Gilbert Graham, whose mother was a passenger. Graham had a suspicious past to say the least. A restaurant owned by Graham’s mother, and managed by Graham, had once been damaged by an explosion; years earlier Graham had been convicted of forgery; and recently he had filed an insurance claim on a pickup truck that had stalled on a railroad track. He also had a motive; before the flight, Graham had taken out a life insurance policy on his mother.












