The legal authorities have started formal procedures to prosecute for graft three senior officials who are thought to be involved in a wider investigation into the former national security chief, Zhou Yongkang. Jiang Jiemin , the former director of the State-owned Assets Supervision and Administration Commission, Wang Yongchun , a deputy manager at China National Petroleum Corporation (CNPC) and former public security deputy minister Li Dongsheng have been detained for alleged corruption, Xinhua reported. The announcement suggests Communist Party leaders are pushing for a resolution in Zhou's case. Sources have said he was detained with family members in December for alleged graft. The South China Morning Post reported yesterday a formal announcement of the findings of the corruption investigation into Zhou could be announced late next month. Jiang was being detained in Yichang in Hubei province with his son Jiang Feng, according to a person familiar with the case. The 60-year-old former head of CNPC, the country's largest oil and gas producer, is said to be a close aide of Zhou. "He was told by investigators during the interrogation that he picked the wrong side," said the source, who asked not be named because of the political sensitivity of the case. The Post first reported in 2012 that Jiang was involved in a cover-up of an accident that killed the son of Ling Jihua , the chief of staff of former president Hu Jintao . Zhou asked Jiang to transfer several dozen million yuan from a China National Petroleum account to help Ling cover up the car crash and prevent details leaking to the public. Jiang, Wang and Li were ousted from the party after a leadership meeting late last month.