In July, a special security force headed by Meng Qingfeng, vice-minister of public security, began to collect evidence it had gathered. It found that 12 financial institutions and individuals were suspected of market manipulation, insider trading and spreading false information to influence stock prices.

Nie said such financial crimes often involve a significant amount of electronic evidence, which can easily be destroyed or lost, so the special force faced difficulties in obtaining solid evidence.

Such crimes also tend to be professional and complex, requiring law enforcement officers to have professional financial knowledge, Nie said.

Prosecutors will step up investigations into abuse of power by officials who collude with suspects to seek benefits, he added.

They will also work closely with financial regulators and share intelligence with them, Nie said.