As a young lieutenant colonel, he was made the commander of the Airborne Brigade in 1954 and was based in Saigon. Towards the end of the May 1955 Battle for Saigon, in which Prime Minister Diệm asserted his rule over the State of Vietnam by defeating the Bình Xuyên organised crime syndicate, some of Diệm's supporters tried to move against some generals whom they accused of questionable loyalty. When he heard that three top generals, including Nguyễn Văn Vy, were being detained in the palace by one of the factions backing Prime Minister Diệm, Trí telephoned and threatened them: "Free the generals in one half-hour or I will destroy the palace and everything inside it."