Sichuan's deputy party secretary has become the first senior official to be targeted in an anti-corruption drive launched by the new leadership.
Li Chuncheng, 56, who was named an alternate member of the Communist Party's Central Committee last month, has been placed under investigation for breaching party discipline.
Sources confirmed Li was put under shuanggui, a disciplinary measure which allows for the detention and interrogation of party members suspected of corruption and other offences.
Li was first named an alternate member of the Central Committee 10 years ago. He lost the seat five years ago, but regained it at the national congress.
Earlier, Li had been tipped to be governor of Henan .
The party's new general secretary, Xi Jinping , said in a speech after his appointment last month that corruption was an urgent problem facing the party. He also warned at a meeting last month the party would lose its hold on power or risk major social unrest unless widespread corruption was curbed.
Li Keqiang , who will become premier in March, and Wang Qishan , head of the party's anti-graft agency, have also pledged to build up a clean team of cadres dedicated to the public good.
From the 1970s to 1998, Li spent most of his time in Harbin , Heilongjiang , first as a student and then in various positions, including deputy chief of the city's branch of the Communist Youth League and deputy mayor.
He was appointed deputy mayor of Chengdu , Sichuan's provincial capital, in 1998, and promoted to mayor in 2001. Four years later, he was named party chief of Chengdu. He became the province's deputy party chief in September last year. He was regarded as a key architect of Chengdu's building boom, and dismayed Premier Wen Jiabao with a vanity project in 2008, after the province was hit by a massive earthquake.
Staff began moving into a new city government headquarters, which reportedly cost more than US$176 million, following the earthquake. Wen visited the headquarters after travelling to the quake-hit area, but left "in disgust, having spent less than three minutes in it", according to a US diplomatic cable released by WikiLeaks last year.
It said Li then announced the headquarters would be sold to private developers and the money raised used to support reconstruction efforts.
There has been speculation that the investigation into Li might be related to allegations of corruption against Chengdu Industry Investment Group chairman Dai Xiaoming, who has been under investigation since August over claims he offered advantages to politicians when pushing for a petroleum project.