This timeline from 2013 has been updated on July 30, 2014.
Zhou Yongkang, who retired last year from the Chinese Communist Party’s supreme decision making body, is facing an investigation on charges of corruption.
The decision to carry out the highest-level corruption investigation in recent Chinese history was made at the Communist Party’s annual summer retreat in Beidaihe near Tianjin earlier this month, sources close to the Chinese government have told the South China Morning Post.
The sources confirm long-standing rumours that Zhou’s downfall was imminent. The former member of the all-powerful Politburo Standing Committee with a cadre family background was a key ally of disgraced former Chongqing Party Secretary Bo Xilai who also has red pedigree. Bo’s trial on charges of corruption, embezzlement and abuse of power concluded earlier this week in Jinan, Shandong province.
Sources tell the Post that Zhou’s downfall was not politically motivated and only remotely related to Bo’s fate. The investigation into Zhou will focus on economic crimes committed when he worked for China National Petroleum Corporation, one of China's largest oil producers, and as party secretary of Sichuan province, sources said.
The investigation might not be publicised until the Third Plenum of the Communist Party’s Central Committee scheduled in November, they say. Yet, a series of investigations in Sichuan province and into people working at CNPC point to a large-scale effort to collect evidence and clamp down on Zhou's network.
SCMP.com looks back at Zhou’s life and the recent corruption investigations that have been linked to his allies and former colleagues: