Police in southwest China’s Kunming said on Monday that they will prosecute 20 people involved with Fanya Metals Exchange, including the head of the exchange, Shan Jiuliang.

Kunming police said that Shan, along with 19 others, had had their cases sent to the prosecutor for review on June 30, the next legal step in the process before they face trial. Police also said the investigation continued and they were working hard to recover stolen assets.

Launched in 2011, the Fanya exchange advertised itself as a state-supported organization aimed at boosting prices of strategic metals mined in China. It offered an investment product promising annual returns as high as 13.68 percent and the flexibility to deposit and withdraw money at will.