A Zhejiang Province woman went from running a foot-massage parlor to owning a huge conglomerate, and police now want to know how she acquired billions of yuan in assets virtually overnight.

The 26-year-old business tycoon, Wu Ying, was detained on Saturday by authorities in the city of Dongyang while they comb through her books and investigate the financial connections she used to establish her Bense Group, according to a report in the Youth Times.

"All creditors associated with Wu and the Bense Group are required to file notices with police outlining their debts," said a government statement obtained by the Zhejiang-based newspaper.

Wu, a Dongyang native, entered the media spotlight last August after she registered 12 companies and bought more than 100 shops in Dongyang.

Her business range covers hotels, department stores, automobile services, decoration materials, entertainment and even Internet cafes. Earlier media reports estimated her assets at 3.8 billion yuan ($475 million).

In a giving spree that started last September, Wu donated 6.3 million yuan to charity within three months, placing her 95th on a ranking of top philanthropists on China's mainland, the newspaper said.

Prior to her splashy debut, however, Wu's business resume was nearly blank.

She was reported to be the oldest child in a farm family in Dongyang's Geshan Town. She quit her accounting studies at a vocational school to run a beauty salon and foot- massage business in her hometown in the late 1990s.

Later, she reportedly opened a small car rental business with friends in Yiwu, another small city in Zhejiang.

But from there the trail vanishes, until last August when she registered the Bense Group, according to the Nanfang Daily, a Guangzhou-based news weekly.

Suspicions about the source of Wu's sudden fortune have swept the Chinese media.

On January 24, she held a news conference in Hangzhou to claim that her money was "clean." She said she acquired her capital from speculating in jewelry, foreign trade, real estate and futures.

She admitted that her company had been investigated by police.

"But my company is OK now," Wu told reporters at the press conference.