A trader who operated out of his West London home was arrested by British authorities Tuesday on US charges that he helped cause the Dow Jones Industrial Average to plummet 1,000 points on May 6, 2010, in what came to be known as the “flash crash”.

Prosecutors and regulators charged Navinder Sarao with using a souped-up version of commercially available software to manipulate a stock-market index futures contract, laying the groundwork for the index's decline, in which hundreds of stocks momentarily lost nearly all their value.