During the 1950s, Tung was a high-ranking official in Nhu's Cần Lao, a secret political apparatus which maintained the Ngô family's grip on power, extorting money from wealthy businessmen.

His period at the helm of South Vietnam's elite troops was noted mostly for his work in repressing dissidents, rather than fighting the Viet Cong insurgents.

However, the pair were unaware that General Tôn Thất Đính, who was planning the phony operation, was involved in the real coup plot.

As a high-ranking official in Nhu's Cần Lao,[2] the secret Catholic political apparatus which maintained the Ngô family's grip on power, Tung raised party funds by extorting money from wealthy businessmen.

[7] He did not conduct operations against the communist Việt Cộng insurgents, but used his forces mainly in Saigon to repress opponents of the Diệm regime.

[9] On 21 August 1963, Tung's men, acting on Nhu's orders, raided the Xá Lợi Pagoda, Saigon's main Buddhist temple.

[11] The attacks occurred after Nhu had tricked a group of Army of the Republic of Vietnam (ARVN) generals into agreeing to declare martial law.

He knew the generals were plotting and hoped to exploit martial law to overthrow his brother, but outmanoeuvred them by sending Tung's special forces into the pagodas disguised as regular ARVN soldiers.

[12] As a result, South Vietnam's Buddhist majority initially thought the regular army had attacked the monks, damaging its generals' credibility among the populace as potential leaders of the country.

As more people made pilgrimages to the pond, so disquiet grew among the district chief and his subordinates, who answered to Ngô Đình Cẩn, another younger brother of Diệm.

[16] Tung also headed a group run by the CIA, in which ARVN personnel of northern origin infiltrated North Vietnam, posing as locals.

The second expedition resulted in the suspension of funding for the special forces until they were placed under the command of the army's Joint General Staff (JGS) and sent into battle.

[23] The Americans were aware that removing the special forces from Saigon would increase the chances that a coup would succeed, thereby encouraging the army to overthrow the president.

[24] In private talks with US officials, Diệm insisted that the army was responsible for the pagoda attacks and that Tung's men were already under the control of the JGS.

[26] Nhu ordered Tung and Tôn Thất Đính – a loyalist general who commanded the ARVN III Corps which encompassed the Saigon region[10] – to plan a fake coup against the government.

[26] Codenamed Operation Bravo, the first stage of the scheme involved some of Tung's loyalist soldiers, disguised as insurgents, faking a coup.

Tung's men and some of Nhu's underworld connections were also to kill some figures who were assisting the conspirators, such as the titular but relatively powerless Vice President Nguyễn Ngọc Thơ, CIA officer Lucien Conein, who was on assignment in Vietnam as a military adviser, and Ambassador Lodge.

In an attempt to outwit Tung, Đính said that fresh troops were needed,[30] opining: If we move reserves into the city, the Americans will be angry.

[30] On 1 November 1963, Tung was summoned by the coup organisers to the Joint General Staff headquarters near Tân Sơn Nhứt Air Base, on the pretext of a routine officers' lunch meeting.

[35][36] The generals were aware of the threat Tung posed; they had discussed his elimination during their planning,[37][38] having contemplated waging an offensive against his special forces.

[39] At nightfall he was taken with Major Lê Quang Triệu, his brother and deputy,[15][32] hands tied, into a jeep and driven to edge of the air base.