Sun pleaded guilty at an open court hearing held on April 12th.
Sun fell from grace just months before the Communist Party met for its twice-a-decade conference in October, and a generational transfer of power was made in key decision-making bodies.
Sun Zhengcai, former member of the Politburo of the Communist Party of China and former Secretary of the Chongqing Municipal Committee, was sentenced[press release] to life in prison on Tuesday for taking bribes. In order to retrieve his "illegal gains", authorities are set to confiscate Sun's property and he will be deprived of his political rights for the rest of his life.
The court said the defendant had been given a "lenient" sentence in light of his willingness to cooperate with the investigation.
Sun said he would not appeal the sentence. Shortly after the investigation was announced, Mr. Xi promoted a protégé, Chen Min'er, to take over as party chief in Chongqing.
Mr Xi has presided over a popular anti-graft drive since coming to power in 2012 that has punished more than one million officials.
Chinese news outlet Caixin had reported that Sun's "designated parties" included two businesswomen.
In such political cases, investigators generally have little difficulty finding evidence of corruption, given the opportunities to exploit one's office and the large family networks eager to take advantage, Ding said. In February, Sun was charged with bribery by prosecutors in Tianjin.
During the 19th National Congress of the Communist Party of China, where the president was granted a second term, Liu Shiyu, chairman of the China Securities Regulatory Commission, described Sun and other political criminals as "figures in important and high places who were both corrupted and contrived to usurp the leadership of the party and seize power".
Sun was the first serving member of the 25-person politburo to be investigated since Bo Xilai, another former Chongqing leader who was jailed for life in 2013.