The has reported that Zhou is being investigated by party disciplinary authorities, although it remains unclear what, if any, action authorities will take against him. Wu is believed to have financial ties to Zhou.

Records in the public domain show that Wu has overlapping business interests with the family of Zeng, who was a former patron of Zhou. Zeng, 74, was vice-president and a member of the Politburo Standing Committee until five years ago.

Wu's business empire, under the banner of Zhongxu, covers a wide range of industries including power station construction, real estate development and entertainment, according to mainland media reports and public documents. A subsidiary, Zhongxu Limited, is registered in Hong Kong.

Hong Kong-listed mainland developer Fantasia Holdings provides a key link between Wu and Zeng's family. Fantasia Holdings' largest shareholder and executive director is Baby Zeng Jie, better known as Zeng Baobao, who is a niece of Zeng Qinghong.

The company holds a controlling 58.8 per cent interest in Fantasia Chengdu Development, Zhongxu holds 10 per cent, while a person named Qiu Qiongming controls the remaining 31.2 per cent, according to Fantasia's prospectus for its 2009 listing. Qiu's identity is unknown, although the person has the same family name as Wu's wife, sources said.

The subsidiary owns at least 12 properties including Chengdu Hailrun Plaza, which has one of the tallest buildings in the city, and Fantasia Town, named after the company, according to Fantasia Holdings' 2013 interim report.

The Chengdu subsidiary was set up in 2001, when Li Chuncheng was deputy party boss and acting mayor of the city before being promoted as its party boss in 2003. In 2009, the municipal government gave Fantasia Chengdu Development the highest award a property developer can receive in the city.

Li was taken away by the party's anti-graft watchdog in December last year.

Most of Fantasia Holdings' land reserves are in Chengdu, accounting for 52 per cent of the company's land bank, according to its 2013 interim report.

The company's website says it manages assets worth more than 24.5 billion yuan (HK$30.9 billion). Zeng Baobao, who founded Fantasia Group (China) in 1996 and was the latter's chairwoman between 2006 and 2011, held a 61.3 per cent stake in the listed company as of June 30 this year, worth about HK$4 billion.

Fantasia Holdings has sought to distance itself from Zhongxu.

"Sichuan Zhongxu has already exited from the project corporate [sic] with Fantasia. Also, Mr Wu Bing [of] Sichuan Zhongxu has no relationship or any connection with Fantasia, Chengdu Fantasia or any affiliate company," the firm said in a written reply to the via e-mail.

Fantasia refused to comment on whether Qiu, the shareholder listed in its 2009 prospectus, had any link with Wu's wife. And it gave no information about when Zhongxu exited Fantasia's Chengdu subsidiary.

Wu also appears to have had close contact with Zeng Qinghuai, elder brother of Zeng Qinghong and Zeng Baobao's father.

In 2002, Zhongxu and China Cultural City Limited, headed by Zeng Qinghuai, co-hosted a gala to celebrate the Mid-Autumn Festival in Hong Kong. The song-and-dance show at the Cultural Centre was attended by well-known mainland singers, including Peng Liyuan , wife of President Xi Jinping .

In 2010, Zhongxu Investment sponsored another high-profile concert organised by Zeng Qinghuai. It featured the Italian operatic tenor Andrea Bocelli, concert pianist Lang Lang and Song Zuying, a PLA singer.

Ahead of the concert, Zeng Qinghuai praised Wu Bing's company. "They have been very supportive of this concert," he said. "That's because they love the motherland, and love folk music deeply."

A year later, Wu's company funded a calligraphy and art exhibition in Jiangsu province. Wu, Zeng Qinghuai and top regional officials attended the opening ceremony.

Zeng Qinghong, right-hand man to former president Jiang Zemin , retired as vice-president in 2008. Prior to that, he was seen as an authority on the country's energy sector.