Sabotage: The Downing of Flight 629
After his initial interview, Jack Graham was released and sent home. But he unknowingly had supplied a great deal of information to the investigating officers. The FBI now had a complete version of Graham's movements during the time immediately before the explosion and details of his actions afterwards. Agents were dispatched to check out virtually every detail of Graham's statements. They found many discrepancies in his story and quickly learned of the simmering animosity between mother and son. On November 13, Graham was asked to return to Denver for an additional interview.
At first, the suspect repeated his assertions that he did not buy his mother the tools in question. He stated that he merely intended to buy them. He could not explain why his wife told investigators that he had indeed bought the tools and placed them inside his mother's luggage. Graham also could not explain the evidence found at his home and the Longmont crash site. But investigators would not relent. Late that afternoon, confronted with the growing mountain of evidence against him, Graham admitted that he caused the explosion on flight 629.
According to the FBI, Graham said that he put together a bomb consisting of 25 sticks of commercial dynamite, two blaster caps, a timer with a maximum capability of 90 minutes and a small battery. He said that he wrapped up the device like a Christmas present and placed it in his mother's luggage just before she left the house for Stapleton. He had set the timer for 90 minutes. Graham said that he knew he had to hurry in order to get his mother on the plane and in flight before the time would expire. After he put his mother on the flight to Seattle, he went to the airport coffee shop, where he had coffee and munched on donuts. When he heard the news that a plane went down outside the City of Longmont, he knew that his bomb had worked.
Investigators were stunned by Graham's matter-of-fact recital of how he killed 43 people to cover up the murder of his own mother. Graham was unapologetic, yet he assisted the FBI with many details of the plot including where and when he purchased the parts of the bomb. Guided by his admissions, Graham was later identified by the clerk in a hardware store where he purchased the dynamite several weeks before.
On November 14, 1955, Jack Gilbert Graham was arrested and charged with 44 counts of murder.