Li Qihong, the celebrated mayor of Zhongshan in South China's Guangdong province, has been placed under investigation for alleged insider trading, local authorities confirmed on Friday.

Li was taken away for questioning by officials of the Central Commission for Discipline Inspection of the Communist Party of China at the end of May, Chen Genkai, Party secretary of Zhongshan, said.

"Li is suspected to have been involved in insider dealing in the stock market and abused her power for personal gains in the city's real estate industry," Chen said.

Five of Li's relatives and five other officials and business representatives suspected to be involved in Li's case, are also being investigated.

Li's husband, Lin Yong'an, 53, was the vice-chairman of the Zhongshan association of golf, while Li's younger brother Li Qiming was the manager of a local property development company.

Both are suspects in the investigation, Chen said.

Li, 54, who was promoted as the mayor of Zhongshan in January 2007, was chosen as one of the top 10 outstanding mayors of China in 2009 due to her work in urban construction, environmental protection, finance and transportation industries.

Reportedly, Li is the first woman mayor to be placed under investigation for economic crimes on the mainland.

Zhongshan Public Utilities Groups Co Ltd, a Shenzhen Stock Exchange listed company, rose to ceiling in 16 successive trading days in August 2007. Li is suspected to be the person behind the unusual growth in the company's stock, according to local media reports.

She allegedly illegally revealed the company's reshuffle in advance.

Tan Qingzhong, chairman of Zhongshan Public Utilities Groups Co Ltd, and the company's general manager Zheng Xuling have also been removed from their posts pending further investigation.

Zhu Lijia, a professor at the Chinese Academy of Governance, said Li's case indicated that the city government's operation lacks transparency.

"Top Party and government officials should publicize their assets and investments to prevent corruption," Zhu said.

Zheng Fenming, a professor at the Guangdong Academy of Social Sciences, said governments at all levels should try to prevent the centralization of power by senior officials to help keep corruption in check.

A transparent and effective system should also be established to expand supervision on major Party and government officials, he added.

More than 100 senior Party and government officials from 21 prefecture-level cities in Guangdong province were sent to attend a three-day anti-corruption course after Li's case came to light.

The special course that ended on Thursday attracted senior officials from the city's discipline inspection commissions, organization departments, public security bureaus, courts and procuratorates.

In addition to attending such classes, the officials were arranged to visit prisons and listen to special lectures by corrupt officials serving jail terms.