Catalytic converters are a vital part of emissions reduction in gas-powered vehicles. But that’s not why they’ve been making headlines. Thieves across the US have been sawing them off cars because they contain precious metals like platinum, palladium and rhodium. Bloomberg Businessweek contributor Evan Ratliff is here to tell the tale of a $500 million catalytic converter theft ring—and how local police departments and federal law enforcement brought it down.