Senior general Mai Chi Tho (alias Nam Xuan), former member of the Political Bureau and former Minister of the Interior (now Ministry of Public Security) was among the founders of the intelligence system in the resistance war against the Americans. After the signing of the Geneva Accords, on October 16th 1954, the Nam Bo regional Party Committee set up the intelligence and counter-intelligence body under the guise of the Research Department. It was led by comrade Le Duan, secretary of the regional Party Committee. The department's head was Van Vien, deputy head was Nam Xuan, and its members were Cao Dang Chiem and Muoi Huong. In mid-1955, Van Vien died in action, so Nam Xuan became department head. The department was entrusted to build and develop the intelligence capacity and thoroughly understand the enemy in all aspects.

The department received agents from many sources from the Southern Viet Nam Police forces such as military police, civil forces and units of intelligence networks. The Research Department operated until 1960, when the intelligence mission was transferred to the Regional Party Committee's Department for Enemy Activities Research, then the Regional Military Intelligence Bureau, and later Regional Intelligence Bureau. In the context of so many ordeals and difficulties when the Southern revolution was drowned in blood, the Research Department was able to lay valuable foundations for the intelligence system. Many intelligence networks established by the Research Department were brought into full play and brilliantly fulfilled their orders in the later stages of the resistance war. Pham Xuan An himself was commissioned by the Research Department.

Nam Xuan said: "Pham Xuan An was fully qualified to be an excellent intelligence agent, if one does not dare call him great. He had all three great virtues: humanity, wisdom and courage.

"Humanity means unselfishness, fidelity, friendliness and charity. Wisdom means a far-sighted vision and a sharp mind. Courage means steadfastness, bravery and a willingness to sacrifice one's life for a just cause. All of these virtues are imbued in Pham Xuan An. He was a true hero.

Nam Xuan began talking about the political situation in which Pham Xuan An worked: "From 1954 to 1959, the rightist movement led the southern regional Party Committee to a very critical situation. From 1954 to 1956, the policy of passive resistance was accepted, because under the Geneva Accords, this was the period before the general election. From July 1957, we were not allowed to wage an armed struggle even though the situation really required that. Only political struggle was allowed. As a result, the revolution suffered heavy losses. In the eastern region of Nam Bo alone, there initially remained a large force of 20,000 cadres. However, in 1959, when we started to launch attacks, this number sharply dropped to about 800.

"Without armed resistance, we couldn't protect ourselves. After the Second World War and the Korean War, the socialist bloc tended to be pacifist, which exerted great pressure on Viet Nam. The southern Party Committee was on the razor's edge. Its members were all well known. It was extremely difficult for them. The regional Party Committee's deputy secretary, comrade Hoang Du Khuong, was arrested. Comrade Le Duan had to leave Sai Gon for Bac Lieu. Comrade Vo Van Kiet, secretary of the Bac Lieu Party Committee was in charge of his security. However, when people saw that there was a person held in high regard, suspicions emerged as to who he could be. Comrade Le Duan grew a beard as a disguise. However, with the beard, he looked slightly like Uncle Ho, which might have drawn people's attention. As a result, he had to leave.

"At last, the regional Party Committee dispatched two members, Hai Xo and Phan Van Dan (with comrade Le Duan), to the north to ask the Party Central Committee to give the green light for armed resistance. They had to wait for over a year. In early 1959, the Party Central Committee convened a meeting, but issued no resolution on this matter. Comrade Le Dun strongly supported armed resistance. Hai Xo and Phan Van Dan went to meet him, saying that they wanted to return to the south. Le Dun told them to meet Uncle Ho. When talking with them, Uncle Ho inquired very carefully about the situation. After hearing them report on the situation, Uncle Ho said: "We cannot let the southern revolution suffer further losses."

"Also during that period, Viet Nam committed errors in land reform. The socialist bloc started to witness initial divisions; Khrushchev publicly denounced Stalin's errors while he was still an icon, since the Soviet Union had been the main force in defeating the fascists. This created more difficulties for the southern revolution. Many comrades had been imprisoned, tortured and murdered. Some, failing to endure atrocious challenges, surrendered to the enemy. Others became demoralized. The Party Central Committee later acknowledged this dark period. Pham Xuan An, as well as many other intelligence agents and the people, were still firmly confident and remained firmly devoted to the revolution although their direct senior leader, Muoi Huong, had been arrested.

"After saying that the revolution in the south could not suffer any further losses, Uncle Ho continued: `The regional Party Committee is the representative of the Party. You are responsible to our people. You must study the situation carefully before making decisions. The central committee is far away and can't grasp the situation as thoroughly as you.' Hearing his words, the two men were inspired and immediately left for the south. At that time, communication was very difficult and it took them six months to reach the regional Party Committee (in late 1959). The regional Party Committee was greatly encouraged by Uncle Ho's guidance and started to prepare for armed resistance. In November, the 15th resolution of the Party Central Committee reached them, allowing them to undertake armed self-defense and Explaining why American intelligence could not plant their men deep in our ranks, Nam Xuan said: "To do that, they had to use their Vietnamese henchmen. However, they always feared death and were unable to endure hardships." Once, in an interview with a foreign journalist, Nam Xuan delivered this remark about American intelligence: "The CIA is qualified in all measures. But their shortcoming is that they invaded our nation. When they came here, they encountered the struggle of tens of million of our people who were determined to defend their fatherland. Their shortcoming lies in their invasion of other nations, rather in their own capability."