Caro Quintero, whose whereabouts are unknown, walked out of a maximum-security prison in August after the appeals court overturned his 40-year sentence for the 1985 torture-killing of U.S. Drug Enforcement Administration agent Enrique Camarena and a Mexican government pilot.
The three-judge appeals court annulled Caro Quintero's sentence on procedural grounds, saying he should have been tried in a state court instead of federal court because Camarena was not formally registered as a diplomat, which would have made it a federal crime. Simple homicides are state crimes.
Prosecutors appealed that ruling and a panel of five Supreme Court justices voted 4-1 Wednesday to overturn the release, ruling that Camarena was a registered U.S. government agent and thus covered by the federal law.
"In his character as a DEA agent, he was an internationally protected person, given that he had been officially recognized by Mexico and the United States, as an intergovernmental agent," the court said in a statement.
A U.S. official who attended the court session, but who was not authorized to be quoted by name, said his government was "satisfied" by the Supreme Court ruling, calling it "the correct decision.
Caro Quintero, 61, would be returned to prison to serve out his sentence under the ruling, but the two governments have not been able to find him since he walked free in the pre-dawn hours of Aug. 9—a release that Mexican prosecutors say they were not advised about until hours after it took place.
Just days after his release, the United States formally requested that Caro Quintero be held for extradition on an unspecified indictment filed in California. Caro Quintero has been charged in two indictments in California, one alleging drug offenses and the other accusing him in Camarena's death. Since Mexican law prohibits extradition on charges already tried in Mexico, he is now likely being sought on the drug charges.
Fellow DEA agents consider Camarena a hero in the war against drug trafficking. The El Paso Intelligence Center, where U.S. federal agencies collect information about Mexican drug barons, is dedicated to him.
The U.S. State Department has announced a reward of up to $5 million for information leading to the arrest and conviction of Caro Quintero, who was a founding member of one of Mexico's earliest and biggest drug cartels.