On June 1931, three agents of International Communist movement in Asia were arrested in Singapore, Hong Kong and Shanghai. A French man arrested in Singapore, Joseph Ducroux, tried to make Singapore a regional center (“hub”) of Communist movement. The person arrested in Hong Kong was Nguyen Ai Quoc, who later became the first president of Vietnam under the name of Ho Chi Minh after the World War II. He was a regional promoter assigned to instruct Communist movements in French Indochina, Siam and British Malaya, and to connect these Southeast Asian movements to Shanghai. The last man arrested in Shanghai was Hilaire Noulens, real name Yakov Matveevich Rudnik, a liaison officer of the Far Eastern Bureau of Comintern.<br>These arrests (which I call the “Noulens Case”) had a strong impact on the International Communist movement in Asia and also on the activity of the British Security System. In this paper, I first reconstruct the International Communist movement in Asia mainly from archival documents on the “Noulens Case” in the Shanghai Municipal Police Files. I then explain how the British Security System monitored this movement and arrested three agents in 1931. The British Security System checked the human movements in and out the empire by combining the Passport Control System with the Political Intelligence such as Special Branch in colonial police. Finally, I analyze the International Communist movement in Asia, the activity of the British Security System, and the impact of “Noulens Case” on these two from the network point of view defined by US physicist Albert-Laszlo Barabasi. In his book “Linked: The New Science of Networks”, Barabasi argues that the key component of the network is the “hub”. Once we focus on “hub”, we can explain the rise and fall of the network, i. e. “the dynamics of the network”.<br>In the International Communist movement in Asia, the “hub” was a liaison officer such as Noulens in Shanghai and a regional promoter such as Nguyen Ai Quoc in Hong Kong. Their arrest meant the disappearance of a “hub” from the movement, and the movement itself was set back severely for a while. On the other hand, from the “Noulens Case”, the British Security System was able to obtain a lot of information about the activity of the International Communist movement in Asia and the agents who joined it.