Federal marijuana distribution conspiracy charges were filed against seven defendants who were arrested during what law enforcement officials said they believe is the largest seizure ever of marijuana in the Chicago area -- conservatively estimated at approximately 21,800 pounds, or nearly 11 tons, packed into six railroad cars from Mexico that arrived at a warehouse in Chicago Heights, Ill., earlier this month. The marijuana is estimated to have a value of approximately $22 million.

According to the FBI, on Nov. 17, 2010, CBP officers in Eagle Pass, Texas, discovered that a Union Pacific train bound for Chicago Heights was carrying approximately 21,800 pounds of suspected marijuana. CBP officers observed a number of large bundled packages, referred to as "super sacks," in six cars on the train. A CBP canine alerted officers to the presence of narcotics in the train cars near several of the super sacks. CBP officers then opened a super sack and observed 13 cubic bundles, which were encrusted in a thick layer of fine red masonry pigment dust. CBP officers broke open several of these cubic bundles and observed a green leafy substance, which field tested positive for the presence of marijuana. In total, CBP officers observed that approximately 109 super sacks in the train cars contained cubic bundles comprised of a green leafy substance. Officers weighed 13 of the cubic bundles from one super sack and determined that they weighed approximately 200 pounds.