The New York Times reports U.S. law enforcement agencies have secretly built up networks of Mexican informants that have allowed them to secretly infiltrate some of that country’s most powerful criminal organizations. Typically, Mexico is kept in the dark about the United States’ actions inside Mexico with its most secret informants. The U.S. informants have reportedly helped Mexican authorities capture or kill about two dozen high-ranking and mid-level drug traffickers. In addition, the informants have sometimes given American counter-narcotics agents access to the top leaders of the cartels they are trying to dismantle.