who was behind the 1964 brinks hotel bombing?
Viet Cong commanders
1964 Brinks Hotel bombing
The Brinks Hotel in Saigon, also known as the Brink Bachelor Officers Quarters (BOQ), was bombed by the Viet Cong on the evening of December 24, 1964, during the Vietnam War. 
wiki:10924981
1964 Brinks Hotel bombing [SEP] Introduction
Second, the bombing would demonstrate to the South Vietnamese that the Americans were vulnerable and could not be relied upon for protection. The bombing prompted debate within the administration of United States President Lyndon B. Johnson. Most of his advisers favored retaliatory bombing of North Vietnam and the introduction of American combat troops, while Johnson preferred the existing strategy of training the Army of the Republic of Vietnam to protect South Vietnam from the Vietcong. In the end, Johnson decided not to take retaliatory action.