BEIJING, Aug. 9 (Xinhua) -- Prosecutors in north China's Tianjin Municipality have approved the arrest of nine suspects involved in a pyramid scheme, the Supreme People's Procuratorate (SPP) said Wednesday.

The nine, suspected of organizing and leading a pyramid scheme, belong to a group called "Diebeilei." Since September 2016, the suspects have recruited nearly 400 members in Tianjin's Jinghai District, the SPP said in a statement.

Nearly 4.9 million yuan (about 730,000 U.S. dollars) was involved in the case.

The suspects, aged between 20 and 30, recruited members under the pretext of job interviews or online dating through social networks such as QQ and WeChat, prosecutors said.