Updated at 6:00 p.m. Eastern
Notorious Mexican drug lord Rafael Caro Quintero has been released after 28 years in prison, multiple U.S. law enforcement sources told CBS News.
Caro Quintero's release comes after a Mexican court overturned his conviction for the 1985 kidnap and killing of a U.S. Drug Enforcement Administration agent. The brutal murder marked a low point in U.S.-Mexico relations.
The court threw out Caro Quintero's 40-year sentence for the murder of Enrique Camarena, ruling on Wednesday that he was improperly tried in a federal court for a crime that should have been treated as a state offense.
The Federal Judiciary Council said the court ordered Caro Quintero released because he had already served his time on other drug-related charges.
Late Friday, the U.S. Department of Justice issued a statement expressing "disappointment" at the drug lord's release.
The Department of Justice, and especially the Drug Enforcement Administration, is extremely disappointed with this result. Caro Quintero was convicted and sentenced in Mexico to serve a 40-year sentence and his early release is deeply troubling.
The Mexican Attorney General's Office said it did not know if there was a current request to extradite him to the United States, where he still faces active charges.
However, the DOJ affirmed that they have maintained an interest in having Quintero extradited to be prosecuted in the U.S.
"In the years since, the Department of Justice 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," the agency said in a statement.
The 61-year-old Caro Quintero is considered the grandfather of Mexican drug trafficking. He established a powerful cartel based in the northwestern Mexican state of Sinaloa that later split into some of Mexico's largest cartels, including the Sinaloa and Juarez cartels.
Caro Quintero is still listed as one of the DEA's five top international fugitives, and U.S. authorities believe he continues to control the laundering of drug money from behind bars.
"Caro Quintero continues to launder the proceeds from narcotics trafficking and he maintains an alliance with drug trafficking organizations such as the Sinaloa Cartel, most notably with Esparragoza Moreno's network," said Treasury Department spokesman John Sullivan, referring to Juan Jose Esparragoza Moreno also known as "El Azul," or "Blue" because of the dark color of his skin who is allegedly a top leader of the Sinaloa cartel.
In June, the Treasury Department imposed sanctions against 18 people and 15 companies that allegedly moved money for Caro Quintero.
"Caro Quintero has used a network of family members and front persons to invest his fortune into ostensibly legitimate companies and real estate projects in the city of Guadalajara" said Adam Szubin, Director of Treasury's Office of Foreign Assets Control. Caro Quintero has spent almost all of his sentence at a prison on the outskirts of that city, Mexico's second-largest city.
Mexico's relations with Washington were badly damaged when Caro Quintero ordered Camarena kidnapped, tortured and killed, purportedly because he was angry about a raid on a 220-acre marijuana plantation in central Mexico named "Rancho Bufalo" Buffalo Ranch that was seized by Mexican authorities at Camarena's insistence.
Camarena was kidnapped on Feb. 7, 1985, in Guadalajara, a major drug trafficking center. His body and that of his Mexican pilot, both showing signs of torture, were found a month later, buried in shallow graves.