On July 19, 2010, the NAV Sarao Milking Markets Fund was registered in Mauritius as part of an umbrella fund running two dozen other strategies, with Mr. Cosgrove as a director. Mr. Sarao three months earlier registered a vehicle with a similar name in the Caribbean island of Nevis.
At the time, “there was no controversy around this individual,” Mr. Cosgrove said. He said the fund never operated or had outside investors after being set up, so was eventually turned over to another investment manager and renamed.
Seems like you are trying to connect dots that may not exist. There is nothing in that article that supports the notion that he was trading for others. It is possible, but they don't actually come out and say that anywhere. It is possible that Sarao was just trying to park money.