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 has sent drug lord Rafael Caro Quintero, who is wanted for the notorious killing of a U.S. DEA agent in 1985, to the United States with 28 other prisoners requested by the U.S. government, the Justice Department confirmed Thursday evening.

After years as one of U.S. authorities' most wanted men, Mexican drug cartel boss Rafael Caro Quintero was brought into a New York courtroom Friday to answer charges that include orchestrating the 1985 killing of a U.