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By Anahi Rama
MEXICO CITY, Aug 9 (Reuters) - Notorious Mexican drug kingpin Rafael Caro Quintero, convicted of ordering the torture and murder of a U.S. anti-drugs agent in 1985, was freed from prison on Friday in a move that angered the U.S. government.
Caro Quintero had served 28 years of a 40-year sentence for the brutal death of Drug Enforcement Administration agent Enrique Camarena and was released after a Mexican court ruled he should have been tried at a state level rather than on federal charges.
The DEA said it was "deeply troubled" by his early release and that it would push for him to be tried in a U.S. court.
"We are reminded every day of the ultimate sacrifice paid by Special Agent Camarena and DEA will vigorously continue its efforts to ensure Caro Quintero faces charges in the United States for the crimes he committed," it said in a statement.
Caro Quintero, who is believed to be 60, holds a special place in Mexican drug lore. He was one of the leaders of the Guadalajara cartel, a forerunner of the Sinaloa cartel which is currently led by Joaquin "Shorty" Guzman, the country's most-wanted drug lord.
Caro Quintero was freed from the Puente Grande prison in the western Mexican state of Jalisco on Friday morning, according to the state attorney general's office.
"There are various factors, and among them the fact that he already served his time for drug trafficking," a court official said in explaining the release.
Camarena was kidnapped, tortured and murdered in retaliation for his involvement in a number of successful drug busts.
At the time, the United States was furious at a perceived lackluster effort to catch Camarena's killer and the episode marked a low point in U.S.-Mexico relations. Caro Quintero was caught in Costa Rica in 1985.
His release raises the possibility of a renewed tussle between the two countries over the possible extradition of the aging drug lord.
U.S. Justice Department spokesman Peter Carr said the government was "extremely disappointed" by the decision to free Caro Quintero and that it "has continued to make clear to Mexican authorities the continued interest of the United States in securing Caro Quintero's extradition so that he might face justice in the United States."
A source from the Mexican attorney general's office said Caro Quintero cannot be extradited to the United States because a decision by Mexico's Supreme Court bars extradition of Mexicans to countries that may impose the death penalty or life imprisonment - punishments excluded by Mexican law.
In June, the U.S. Treasury Department imposed sanctions on 18 people linked to Caro Quintero, including six family members, freezing their U.S. assets.
More than 70,000 people have been killed in drug-related violence in Mexico since 2007 when the government launched a militarized attack on the warring cartels.
President Enrique Pena Nieto, who took office in December, has shifted the focus away from going after cartel bosses to tackling violent crimes such as extortion and kidnapping.
The shift has raised concerns that Mexico may cooperate less with U.S. security forces in the fight against the cartels. (Additional reporting by Tim Gaynor in Phoenix and David Ingram in Washington; Writing and additional reporting by Gabriel Stargardter; Editing by Simon Gardner and Mohammad Zargham)