It wasn't international terrorism. It was most certainly domestic. The bomb wasn't very sophisticated. If it were an international terrorist I would believe there would had been more devastation and the bomb would had been more sophisticated than a pressure cooker with nails and BB's. It was most likely some homegrown idiot within the United States, such as the Newton and theater shootings. Before I actually did a bit of studying I thought maybe it was the Government's way of getting to be able to invade another county that shouldn't be invaded, such as the inside job on 9/11.