MEXICO CITY (AP) — Infamous drug lord Rafael Caro Quintero has walked out of prison 12 years before his sentence was up for the 1985 killing of a U.S. Drug Enforcement Administration agent.

An official of the prosecutors’ office in the western Jalisco state says Caro Quintero was released early Friday, before media were notified of the court order.

The official was not authorized to be quoted by name.

The murder of DEA agent Enrique Camarena damaged U.S.-Mexico relations, but the U.S. Embassy had no immediate comment on his release.

A Mexican court threw out Caro Quintero’s 40-year sentence, ruling he was improperly tried in a federal court for a state offense.

It was unclear whether there was any request to extradite him to the United States, where he still faces active charges.