CHICAGO (CBS) — Seven men have been arrested in a $22 million drug bust, a case federal officials said is the largest single seizure ever of marijuana in the Chicago area.

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Federal officials estimated that nearly 11 tons of marijuana were packed into six railroad cars from Mexico that arrived at a warehouse in south suburban Chicago Heights earlier this month.

CBS 2’s Susanna Song reports that seven men were charged with conspiracy to possess and distribute marijuana and were being held pending detention and preliminary hearings next week, according to the U.S. Attorney’s office.

The defendants were identified as Carlos Osvaldo Quintero, 31, also known as “Carlos Gomez” and “Miguel Dominguez”; his father, Martin Quintero, 63, Felipe de Jesus Magana-Campos, 47, a.k.a. “Padrino”; Eduardo Angel Zalayaran-Ruiz, 54, a.k.a. “Other Inge”; Javier Vera, 24, a.k.a. “Ducky”; Christian Gonzalez, 24, a.k.a. “Chris”; and Miguel Cordova, 20, a.k.a. “Mike.”

“This historic drug seizure represents law enforcement partnership and cooperation at their best,” said Gary J. Hartwig, Special Agent-in-Charge of ICE Homeland Security Investigations (HSI) in Chicago.

Federal prosecutors said that on Nov. 17, U.S. Customs and Border Patrol officers in Texas discovered that a Union Pacific train bound for Chicago Heights was carrying nearly 11 tons of marijuana.

Officers saw a large number of so-called “super sacks” of cannabis packed in six cars on the train.

A canine unit alerted officers to the presence of drugs on the train and officers opened one of the “super sacks” to find 13 bundles encrusted in masonry dust. When officers opened the bundles, they found marijuana packed inside.

However, shipping documents stated the sacks contained packages listed as “titanium pigments” and were being imported by a fake company in Rockdale, Ill., just south of Joliet.

Agents placed the marijuana back into the rail cars and sealed them and, with the railroad’s cooperation, tracked the train as it traveled to a storage warehouse in the 1200 block of South State Road in Chicago Heights.

One defendant, Carlos Osvaldo Quintero, allegedly spoke to a Union Pacific employee on several occasions to coordinate the delivery of the train cars to the warehouse.

From Dec. 6 through 10, the rail cars were unloaded using forklifts to load the packages onto a flatbed truck and then move the packages to a smaller storage facility near the warehouse.

If convicted, the defendants face a minimum of 10 years in prison for each charge and a maximum of life in prison and a $4 million fine.

Federal prosecutors and law enforcement agents were scheduled to discuss details of the case Thursday afternoon at a press conference at the Dirksen Federal Building in downtown Chicago.

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