Last year, the Mexican government finally agreed to extradite the notorious drug kingpin El Chapo to the U.S. Born Joaquín Guzmán Loera, he was once ranked by Forbes as one of the most powerful people in the world. His trial began in New York, on November 5th, and Guzmán faces seventeen counts related to drugs and firearms; prosecutors have said that they will also tie him to more than thirty murders. The government’s star witnesses against the notoriously elusive drug lord are identical twins from Chicago, Pedro and Margarito Flores. While still in their twenties, the Flores brothers became major drug traffickers, importing enormous quantities of drugs from the Sinaloa cartel. They avoided violence and feuds with rivals, but eventually got caught in the middle of a cartel war. It was a dangerous position, and the only way out was to seek government protection. The Flores brothers flipped; they began working secretly for prosecutors—recording their business calls with Guzmán and others—in exchange for leniency in their own trials. Tom Shakeshaft, the former Assistant U.S. Attorney who flipped them, tells The New Yorker’s Patrick Radden Keefe how it all went down.