ROGUE TRADER

AT 6AM on a cold, dark Tuesday morning in April 2015, half-a-dozen plainclothes police officers, two FBI agents and two prosecutors from the US Department of Justice rendezvoused at a McDonald’s on a roundabout near Heathrow Airport in London.

After running through the plan one last time, the group edged out of the car park and onto the suburban streets of Hounslow, eventually coming to a stop outside a beige, two-storey semi-detached that was indistinguishable from those around it.

Inside, asleep and oblivious to his fate, was Navinder Singh Sarao, a 36-year-old trading savant who’d made $70 million (then about R840 million) rapidly buying and selling financial futures using a keyboard and mouse as if playing a computer game. In the US government’s reckoning, he’d also helped precipitate the fastest and most mysterious market collapse in recent history – the so-called “flash crash” of 2010 – when, without warning, markets around the world suddenly tanked, temporarily erasing $1 trillion in stocks.

The Americans had been monitoring Sarao from afar for months, reading his emails, tracing his assets and interviewing his associates. Yet none of the investigators had met him and he remained something of an enigma.

They knew he traded alone from his parents’ house, and though he prided himself on being a stranger to Wall Street, records showed he routinely bought more shares than the world’s largest banks and hedge funds. They’d heard stories of Sarao harassing staff at the Chicago Mercantile Exchange, the electronic marketplace where he plied his trade. One employee was left shaken when Sarao reportedly threatened to cut off his thumbs. Yet Sarao’s brokers described him as a pussycat who got