In November the US Drug Enforcement Administration issued its Drug Threat Assessment. Mexican ‘transnational criminal organisations’, it said, are the primary suppliers of heroin, cocaine, methamphetamine, and marijuana to the United States. Drugs – the DEA says – are killing 46,000 Americans a year. But between Mexico’s criminal enterprises, and their clients, is a vast expanse of difficult geography and an international border. So, how do cartels get drugs into the US? The Inquiry hears from serving US law enforcement personnel tasked with intercepting drugs shipments. Their stories – of tunnels, “narco-subs” and complex criminal networks – are astonishing.

(Photo: Narco-Submarines, Credit: Reuters)