Agents of the U.S. Drug Enforcement Administration and Justice Department officials have met in secret with members of Mexican drug cartels in exchange for information on rival drug organizations, a new extensive investigative report by Mexico's El Universal newspaper startlingly concludes.

According to the report, U.S. agents held more than 50 secret meetings with cartel operatives on Mexican territory between 2000 and 2012 -- without informing Mexican authorities.

El Universal writes:

Without the presence of Mexican authorities, as bilateral agreements stipulate, without informing the Mexican government, the agents of the DEA met with members of the cartels in Mexican territory, to obtain information about their rivals and at the same time and establish at the same time a network of informants of narco-traffickers, who signed cooperation agreements, subject to results, so that they can obtain future benefits, including charges being dropped in the United States.

Several of the documents were related to the Chicago trial of Jesus Vicente Zambada-Niebla, the son of Sinaloa leader Ismael "El Mayo" Zambada.

As Business Insider noted in 2012, Zambada-Niebla alleged while in detention in Chicago that the U.S. government struck a deal with Mexico's Sinaloa cartel to finance and arm the drug traffickers in exchange for information. Zambada-Niebla was arrested after having met with DEA officials, and believed that the alleged deal implied he was immune from arrest or prosecution.

In the emails that the department turned over to congressional investigators, Justice Department officials last October discussed both the Fast and Furious gun-trafficking surveillance operation in Phoenix and a separate investigation from 2006 and 2007 called Operation Wide Receiver. In Wide Receiver, which took place in Tucson, firearms also were acquired by illegal straw purchasers and lost in Mexico, the emails say.