Insight - Flash crash charges garner increasing scepticism in high-speed world

U.S. has asked UK authorities to hand over Navinder Singh Sarao, 36, after his arrest this week on charges that he manipulated markets over several years in a fraudulent scheme that helped cause the stock market rout. The U.S. Department of Justice alleges that Sarao used souped-up, off-the-shelf software to trick other market participants into thinking massive sell orders were about to hit, causing the so-called E-mini S&P futures prices to drop so he could buy at cheaper levels. Linking S