The US first caught wind of Iran’s alleged plan to assassinate a Saudi diplomat when Manssor Arbabsiar contacted Mexico’s Zeta cartel to do the deed—and wound up talking to a DEA agent. But that DEA agent wasn’t specifically targeting Arbabsiar—he was just one of several spies the DEA has peppered throughout Mexico's organized crime, the New York Times reports. The clandestine agents have been credited with numerous busts, but are kept theoretically secret from Mexican authorities.
“The Mexicans sort of roll their eyes and say we know it’s happening, even though it’s not supposed to be happening,” one security expert says. DEA officials say they have “several highly placed confidential sources with direct access” to key leaders in the Zetas and the Gulf Cartel. But issues have arisen from the program—one midlevel Sinaloa boss sentenced last month, for example, used his in with the DEA to pass along info that would hurt rival cartels, while protecting his own trafficking activities.