China's top prosecutor said Monday it has opened a criminal investigation into the former party chief of Chinese mega-city Chongqing, who was expelled from the Communist Party earlier this year following corruption allegations.
Sun Zhengcai, who was once tipped to become a member of the party's top leadership, has had a precipitous fall from grace since he was suddenly removed from office this summer.
He will be investigated for "accepting bribes," according to a brief statement on the website of the Supreme People's Procuratorate.
The decision follows Sun's expulsion from the CCP in September after an investigation by the party's disciplinary body found the politician had abused his position by taking bribes and trading power for sex.
The former member of the party's Politburo was also accused of nepotism, sloth and leaking confidential party information and betraying party principles.
Sun had once been tipped for promotion to the Politburo's elite, seven-member standing committee.
At 53, he was the youngest member of the 25-member Politburo and he was even seen in some quarters as General Secretary Xi Jinping's potential successor.
In October, the CCP accused Sun and two others of attempting to rig leadership elections at top party gatherings, potentially threatening Xi's ascension to the party's top spot.
Sun was the first serving member of the Politburo to be placed under investigation since Bo Xilai, also a former Chongqing party chief who was jailed for life in 2013 in the wake of a massive anti-corruption campaign launched by Xi.
His sweeping crusade against official corruption over the last five years has removed several rivals, leading some analysts to liken it to a political purge.