A U.S. judge on Thursday authorized the seizure of real estate in Mexico that prosecutors said was purchased by a notorious fugitive drug lord wanted for the killing of a federal agent.

The forfeiture order against Rafael Caro Quintero was entered in federal court in Brooklyn. Court papers identify five homes — a combination of gated houses and condos in and around Guadalajara worth several million dollars — allegedly purchased with drug cartel money and put in the name of Quintero’s relatives.

U.S. authorities said they were using diplomatic channels to try to get the order enforced.

The U.S. has long sought the arrest and extradition of Quintero to the United States for the kidnapping and murder of Drug Enforcement Administration Special Agent Enrique Camarena in Mexico in 1985.

Quintero “is one of the world’s most wanted criminals for years of drug trafficking and his role in killing one of our own,” Ray Donovan, head of the DEA’s New York office, said in statement on Thursday.

After years behind bars in Mexico, Caro Quintero was freed in 2013. A Mexican federal court has issued a warrant for his re-arrest, but he remains at large.