MEXICO CITY (AP) — Mexico has sent drug lord Rafael Caro Quintero, who was behind the killing of a U.S. DEA agent in 1985, to the United States with 28 other prisoners requested by the U.S. government, the Mexican government said in a statement Thursday.

Alleged drug cartel boss Rafael Caro Quintero, who spent decades in prison in Mexico for the murder of a U.S. drug enforcement agent, pleaded not guilty in a U.S. court on Friday to drug trafficking charges that could result in his execution.

MEXICO CITY — Mexico extradited 29 alleged drug traffickers to the United States on Thursday, including Rafael Caro Quintero, a prized target long sought in the killing of a U.S. narcotics agent, and two leaders of the hyper-violent Zetas cartel,