Following the rout in China's stock market last week that erased almost US$ 3.9 in market value,  China's Ministry of Public Security said it will help the China Securities Regulatory Commission investigate evidence of “malicious” short selling of stocks and indexes, according to a statement on its website Thursday. Vice Public Security Minister Meng Qingfeng visited the regulator’s offices in Beijing on Thursday, the official Xinhua News Agency said earlier on its microblog.