information:extraction, stylistic:tone
KMT response to Zhou's intelligence work

In late April 1931, Zhou's chief aide in security affairs, Gu Shunzhang, was arrested by the KMT in Wuhan. Gu was a former labor organizer with strong mafia connections and weak commitments to the CCP. Under threat of heavy torture, Gu gave the KMT secret police detailed accounts of underground CCP organizations in Wuhan, leading to the arrest and executions of over ten senior CCP leaders in the city. Gu offered to provide the KMT with details of CCP activities in Shanghai, but only if he could give the information directly to Chiang Kai-shek.

One of Zhou's agents working in Nanjing, Qian Zhuangfei, intercepted a telegram requesting further instructions from Nanjing on how to proceed, and abandoned his cover to personally warn Zhou of the impending crackdown. The two days before Gu arrived in Nanjing to meet with Chiang gave Zhou time to evacuate Party members and to change the communication codes used by Teke, all of which were known to Gu. After meeting briefly with Chiang in Nanjing, Gu arrived in Shanghai and assisted the KMT secret police in raiding CCP offices and residences, capturing members who could not be evacuated in time. The summary executions of those suspected of Communist sympathies resulted in the largest death-toll since the Shanghai massacre of 1927.

Zhou's reaction to Gu's betrayal was extreme. More than fifteen members of Gu's family, some of whom worked for Teke, were murdered by the Red Squad and buried in quiet residential areas of Shanghai. The Red Squad then assassinated Wang Bing, a leading member of the KMT secret police who was known for moving around Shanghai in rickshaws, without the protection of bodyguards. Most surviving CCP members were relocated to the Communist base in Jiangxi. Because most senior staff had become exposed by Gu, most of its best agents were also relocated. Zhou's most senior aide not yet under suspicion, Pan Hannian, became Teke' s director.

The night before he was scheduled to leave Shanghai in June 1931, Xiang Zhongfa, who was one of Zhou's most senior agents, decided to spend the night in a hotel with his mistress, ignoring Zhou's warnings about the danger. In the morning, a KMT informant who had been trailing Xiang spotted him as he was leaving the hotel. Xiang was immediately arrested and imprisoned within the French Concession. Zhou attempted to prevent Xiang's expected extradition to KMT-controlled China by having his agents bribe the chief of police in the French Concession, but the KMT authorities appealed directly to the authorities of the French Concession, ensuring that the chief of police could not intervene. Zhou's hopes that Xiang would be transferred to Nanjing, giving him an opportunity to kidnap Xiang, also came to naught. The French agreed to transfer Xiang to the Shanghai Garrison Headquarters, under the command of General Xiong Shihui, who subjected Xiang to relentless torture and interrogation. Once he became convinced that Xiang had given his torturers all the information that they requested, Chiang Kai-shek ordered Xiang to be executed.

Zhou Enlai later succeeded in secretly purchasing a copy of Xiang's interrogation records. The records showed that Xiang had disclosed everything to the KMT authorities before his execution, including the location of Zhou's residence. Another round of arrests and executions followed Xiang's capture, but Zhou and his wife were able to escape capture because they had abandoned their apartment on the morning of Xiang's arrest. After establishing a new Politburo Standing Committee in Shanghai, Zhou and his wife relocated to the Communist base in Jiangxi near the end of 1931. By the time Zhou left Shanghai, he was one of the most wanted men in China.