A top Chinese political adviser, who was once an aide to ex-security chief Zhou Yongkang, is being investigated for corruption, the government says.
Sichuan official Li Chongxi is suspected of "serious discipline and legal violations".
President Xi Jinping has said that battling corruption in the Communist Party is a top priority.
On Saturday, state media said more than 500 officials in Hunan resigned following an election bribery scandal.
"Li Chongxi, chair of Sichuan province's Chinese People's Political Consultative Conference, is currently being investigated for suspected serious disciplinary and legal violations," the Communist Party watchdog said in a statement on its website.
The statement gave no other details. The term "serious disciplinary violations" is used to refer to corruption by Communist Party members.
Former energy chief Jiang Jiemin and ex-Sichuan deputy party chief Li Chuncheng are also being investigated for corruption. Both have worked with Zhou Yongkang, one of China's top former leaders, before.
For months, there have been rumours and reports that Mr Zhou is being investigated for corruption, correspondents say.
Mr Zhou, a former member of China's Standing Committee, China's most powerful political body, was the patron of disgraced politician Bo Xilai, who was given a life sentence earlier this year for bribery and abuse of power.
Xi Jinping has warned that corruption could topple the Communist Party, and launched an anti-corruption campaign he said would target both "tigers and flies" - high and low ranking officials in the government.
Internet users are also increasingly pursuing those perceived as having done wrong through online exposes and campaigns.
But there have been signs that this has worried the authorities, with a number of journalists arrested for "rumour-mongering" and a high-profile blogger arrested.