People from as far away as the United States say they have lost money in a Hong Kong-based online auction scheme, as the number of complaints received by police in the city increased more than five-fold in two months. The case centres on Bidders' Paradise, a Tsim Sha Tsui-based auction company founded by the son of a prominent clergyman. Officers from the commercial crime bureau raided its offices in New Mandarin Plaza and homes across the city in February. Since then, the number of complaints has increased from 17 to more than 100, a police source said. Officers say the scheme involved HK$50 million. The founder, Luke Teng, and four female promoters were arrested on suspicion of conspiracy to defraud. Police sources said investigators were also studying whether the scheme breached a law introduced in 2012 to prohibit pyramid selling. People who joined the scheme complained that they were unable to withdraw the cash rewards they had built up by making bids or referring friends to the website. As many as 50,000 Hongkongers might have joined, police sources said. They put in at least HK$10,000 each and received points to bid for items such as phones, watches and handbags offered for below market rates. American members believe thousands there joined the scheme. "The case had some elements of an illegal pyramid scheme … but we have yet to analyse witness statements," a police source said. Pyramid schemes are defined as ventures in which rewards are entirely or substantially based on the recruitment of new members. Teng did not respond to requests for comment. Companies Registry filings show he registered the firm in June 2013. Teng is the son of the late Reverend Philip Teng Jinhui, who led the North Point Alliance Church for decades and served as a translator for American evangelist Billy Graham on his first visit to China in the late 1980s. Hongkongers who joined Bidders' Paradise said they were able to withdraw small amounts of cash at first, but had been rejected since April last year. In some cases, they were told the company was short of cash. US members told the Post of similar experiences, dating back as far as November 2013. Jeff Johnson, 57, a therapist from Los Angeles, joined in December 2013. After paying US$10,000 for points to make bids, he successfully bid US$500 for a MacBook Air, but was told he would have to buy the product and receive a rebate on the difference in price in the form of more points. He paid US$1,100 for the computer, but got nothing back. He and 400 other angry members demanded their money back from the scheme's US promoters at a conference in Las Vegas in March last year. Some said they had lost up to US$100,000. But Everett Hale, a promoter of the scheme from Las Vegas, said it was legitimate, and insisted some participants "chose not to understand" the company's business model. He said he was one of more than 100,000 independent distrubutors worldwide. Teng and the four women have not been charged and must report back to police next month.