WASHINGTON (Reuters) - A veteran Mexican drug lord drug, who is accused of murdering a federal agent in 1985, was added to the FBI’s “Ten Most Wanted Fugitives” list on Thursday after a newly unsealed indictment charged him for his continued criminal drug activities.

Rafael Caro Quintero, a well-known Mexican drug lord, now faces additional criminal charges unsealed in a federal court in Brooklyn, New York, and the government is offering a $20 million reward for information leading to his arrest.

U.S. law enforcement said Thursday they believed Caro Quintero was still an active member of the infamous Mexican Sinaloa drug cartel.

“We need the public’s help in finding this violent fugitive,” FBI Deputy Director David Bowdich said Thursday.

Caro Quintero was previously convicted of ordering the murder of DEA Special Agent Enrique “Kike” Camarena and served 28 years in a Mexican prison before being released on a technicality in 2013.

Several years ago, in an interview with Mexican magazine Proceso, he denied murdering Camarena. He also recently told the Huffington Post he is not a drug trafficker or cartel leader.

Robert Patterson, acting head of the Drug Enforcement Administration, dismissed such claims on Thursday, saying the DEA was certain he is an active member of the Sinaloa cartel.

“We know he is, and he also knows he is,” he said.

Thursday marked the first time that a DEA fugitive has been added to the FBI’s list of the top 10 most wanted fugitives. Since the list’s inception, there have been 518 people added to it.

A federal warrant for Caro Quintero was issued in 1992 out of a federal court in Los Angeles, when he was charged with violent crimes as part of a racketeering scheme, conspiracy to kidnap a federal agent, kidnapping a federal agent, murdering a federal agent and other related crimes.

The DEA and FBI’s renewed push to track down Caro Quintero comes at a time when the Justice Department under Attorney General Jeff Sessions’ tenure is prioritizing enforcement against violent crimes and drug trafficking.

Recently, Sessions urged federal prosecutors to seek the death penalty in drug cases when it is appropriate under law to do so.

The renewed push to arrest Caro Quintero comes a few months before Joaquin Guzman, the Mexican drug lord known as “El Chapo,” is slated to go on trial in September for his leadership role in running a global drug trafficking operation as leader of the Sinaloa Cartel.