Quannengshen, or The Church of Almighty God, is a secretive organization, and the biggest mystery surrounds its financial operations.

In 2009, the sect used underground banks to transfer more than 100 million yuan ($16 million) in donations from followers on the mainland to Hong Kong, according to Yeung Tze-chung, general secretary of the Concern Group on Newly Emerged Religions. He believes the money is used to buy ad space in newspapers, distribute pamphlets and organize meetings.

Many people in provinces such as Henan, Liaoning, Shandong and Anhui told reporters that family members had stolen money and donated it to the cult. "My wife had donated at least 30,000 yuan before she disappeared from home three years ago," said Ling Zhanzhang, from Henan.

Critics say Quannengshen's leaders make full use of Hong Kong's links with the mainland, and its tolerance of law-abiding outsiders.

"In their plan, Hong Kong is a center for channeling their financial resources overseas. It's also a venue for big conferences, because it's much easier for followers from the mainland to visit Hong Kong than another hub, such as South Korea, or its headquarters in the United States," Yeung said.

However, after several Quannengshen members were accused of the murder of a woman at a McDonald's restaurant in Zhaoyuan, Shandong province, the cult has lain low in Hong Kong. "It's better for members in Hong Kong to maintain a low profile right now. Most of them have relatives on the mainland, and if they were to cross the border for a family visit, they could be identified and arrested by the authorities," Yeung said.