In 1927, the Kuomintang reactionaries set off the "412 counter-revolutionary" action, Shanghai became a white terror zone, in order to ensure the safety of the people, they became the "special department" responsible for the protection, under the arrangement of the special department, Qian Zhuangfei and Hu Di respectively entered the national secret service department, and Li Kenong formed an intelligence team, the three of them were called "Longtan Sanjie", which means that they worked in the tiger's den in Longtan, and these three people also made great contributions at that time. So what happened to the three of them? 
Qian Zhuangfei is a native of Wuxing, Zhejiang, studied in Huzhou Middle School in his early years, and was later admitted to Beijing Medical College, came to Shanghai in 1928, under the arrangement of the party organization, he participated in the Kuomintang radio training class, and this opportunity to break into the Kuomintang internal ** investigation department, that is, the later Zhongtong. Xu Enzeng was the chief of the investigation section at the time, Qian Zhuangfei became his confidential secretary, in 1931, one of the leaders of the ** special branch Gu Shunzhang mutinied, Qian Zhuangfei intercepted the secret report, quickly spread the news to Shanghai, ** and others took emergency measures to evacuate, to avoid a big disaster, after the incident, Qian Zhuangfei understood that his identity was exposed, had to leave for the Soviet area, once served as the director of the Red Army Security Bureau, deputy director of the Second Bureau of the General Staff, etc., in 1935 during the Long March, Qian Zhuangfei mysteriously disappeared in the Wujiang area, was posthumously named a martyr, ** after many affectionate words, "If it weren't for Comrade Qian Zhuangfei, our comrades working in Shanghai would have died long ago."
Hu Di is a native of Shucheng, Anhui Province, in 1924, when Hu Di went to school in Beijing, he met Qian Zhuangfei, the two became close friends, a year later, the two joined the Communist Party together, in the spring of 1928, Hu Di was introduced by Qian Zhuangfei to work in the Shanghai Radio Administration, and then he broke into the Kuomintang secret service in Nanjing, providing a large number of important military secret information for the red base area. In 1930, Hu Di in Tianjin to build the Great Wall News Agency, which is the Kuomintang secret service in the north of the branch, Hu Di as the president, Gu Shunzhang after the rebellion, Li Kenong at that time to Hu Di sent a telegram "Hu Di, Ke Chao is sick" meaning that the matter is serious, need to be evacuated urgently, Hu Di received the telegram, immediately took a foreign ship to leave Tianjin, and then he and Qian Zhuangfei went to the ** Soviet area. 
In the Soviet area, Hu Di served as the chief of the interrogation section of the Executive Department of the Political Security Bureau, the chief of the reconnaissance section, etc., in 1935, Zhang Guotao led the army to engage in **Red Army**, Hu Di was very angry with his behavior, often said some dissatisfied words, Zhang Guotao knew that he slandered him as a Kuomintang spy, and then killed him secretly, Hu Di's death was a complete unjust. Li Kenong is a native of Chaoxian County, Anhui Province, he is the last person in the ending of the Longtan Sanjie, in 1929 he entered the Shanghai Radio Administration, as the head of the special service unit, after Gu Shunzhang defected, Qian Zhuangfei sent people to find him first, and then that day happened not to be the day he met with Chen Geng, he looked for them one by one, and finally found *** Then they evacuated unified, and shortly thereafter, Li Kenong also went to the **Soviet area. 
In the Soviet area, Li Kenong served as the head of the Executive Department of the State Political Security Bureau, the head of the Red Army Work Department, and then served as the secretary general of the Eighth Route Army Headquarters, the head of the Social Department, etc., in 1955, Li Kenong was awarded the rank of general, ** once said that "Li Kenong is China's big spy, but he is just a big spy of the Communist Party." In 1962, Li Kenong died of illness.