(ShareCast News) - Shares in Man Group slumped following a press report that the chairman of the hedge fund manager's China unit, Li Yifei, has been taken into custody by Chinese authorities to assist with a police probe into market volatility.According to Bloomberg, which cited people familiar with the matter, authorities are looking into the cause of the sharp swings seen in the Chinese stock market recently.Li's husband said in a telephone interview that she is in a meeting with "relevant industry authorities" and he doesn't know who they are, Bloomberg reported. He said he spoke to her on the phone and expects her back home soon but does not know when.Atif Latif, director of trading at Guardian Stockbrokers, said the lack of detail on this story is weighing on Man, but some of the downside is also due to general weakness in the market."The AHL fund has performed well through the recent market volatility and given the strong price action in the last three months we have seen some natural profit taking and reallocation of capital into other names," he said.At 0950, Man Group shares were down 6.5% at 150.60p.