The Drug Enforcement Agency, tasked with protecting Americans from drug rings, is now inviting them into the United States from Mexico. What could possibly go wrong?

U.S. federal agents allegedly allowed the Sinaloa drug cartel to traffic several tons of cocaine into the United States in exchange for information about rival cartels, according to court documents filed in a U.S. federal court.

The allegations are part of the defense of Vicente Zambada-Niebla, who was extradited to the United States to face drug-trafficking charges in Chicago. He is also a top lieutenant of drug kingpin Joaquin "Chapo" Guzman and the son of Ismael "Mayo" Zambada-Garcia, believed to be the brains behind the Sinaloa cartel.

The case could prove to be a bombshell on par with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives' "Operation Fast and Furious," except that instead of U.S. guns being allowed to walk across the border, the Sinaloa cartel was allowed to bring drugs into the United States. Zambada-Niebla claims he was permitted to smuggle drugs from 2004 until his arrest in 2009.

Randall Samborn, assistant U.S. attorney and spokesman for the Justice Department in Chicago, declined comment.