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 extradited notorious drug lord Rafael Caro Quintero and 28 other fugitive cartel members to the United States, according to the US Department of Justice. Caro Quintero, considered by Mexican authorities to be the founder of the Guadalajara cartel,

Trump designated drug cartels terrorist organizations and Mexico extradited 29 alleged members, one a suspect in a notorious DEA killing in 1985.