November 1955, A United Airlines DC-3 flight 629 had just departed Stapleton Airport at Denver with a full crew and passengers when air traffic controllers in the control tower saw two flashes from the DC-3 and then the plane disappeared. FBI Director, J. Edgar Hover assigned over two dozen FBI agents to the investigation.  Working in conjunction with the Civil Aeronautical Board CAB) the FBI had gathered the plane wreckage and re-assembled the DC-3 in a hanger at Stapleton Airport.

This was the first time an American airline carrier had ever been subjected to terrorist attack and it was the first time that an aircraft had been restored after a crash. The reconstruction of the DC-3 revealed that a bomb had been place on board the aircraft. Within two weeks the FBI through its investigation had determined that a Jack Graham had placed a bomb in the luggage of a passenger on board the DC-3. The passenger was Jacks mother. Jack had placed the bomb in his mothers luggage in order that he could collect on a $37,000. life insurance policy.  Had Jack Graham been able to get a way with the bombing he would not have been able to cash the life insurance policy in as his mother had forgot to sign the policy.  Jack Graham had admitted to the bombing and was sentence to death by the gas chamber.