The Department of Justice on Friday announced charges in a fentanyl-trafficking investigation against more than two dozen members of Mexico’s Sinaloa cartel, including the four sons of now-imprisoned cartel leader El Chapo, known as “the Chapitos.”

Attorney General Merrick Garland said the charges take aim at “the largest, most violent, and most prolific fentanyl trafficking operation in the world – run by the Sinaloa Cartel, and fueled by Chinese precursor chemical and pharmaceutical companies.”

Garland said the charges target suppliers in China who sell fentanyl precursors to the cartel, a Guatemalan-based broker who purchases the chemicals on behalf of the cartel, operators of labs in Mexico where the cartel manufactures fentanyl, a weapons supplier who provides the cartel with firearms smuggled into Mexico from the U.S., leaders of the cartel’s security forces, money launderers and the cartel’s leaders.

According to the indictments, 28 people were charged in the Southern District of New York, four in the Northern District of Illinois and another in the District of Columbia. Some were charged in more than one indictment. Eight of the defendants are in the custody of international partners, and the U.S. will be seeking their extradition, Garland said.

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Treasury Department sanctions Chinese entities

Meanwhile, the U.S. Treasury Department announced sanctions against two Chinese entities and five people based in China and Guatemala for allegedly supplying precursor chemicals to the cartel for the production of illicit fentanyl “intended for U.S. markets.” Four of those individuals have been charged by the Justice Department, Garland said.

State Department announces rewards for information on ‘the Chapitos’

The U.S. Department of State announced rewards for information leading to the arrest or conviction of 27 people involved in fentanyl trafficking, including up to $10 million for Ivan Guzman Salazar, Alfredo Guzman Salazar and Ovidio Guzman Lopez, and up to $5 million for Joaquin Guzman Lopez – known as “the Chapitos.” Ovidio Guzmán was arrested in Mexico earlier this year.