NEW YORK (AP) — Ismael “El Mayo” Zambada, a longtime leader of Mexico’s Sinaloa cartel who is facing drug trafficking charges in a U.S. court, appeared for the first time Friday before the judge who is presiding over his case.

Zambada, 76, appeared at a status conference in Brooklyn federal court before District Court Judge Brian Cogan, who sentenced fellow cartel kingpin Joaquín “El Chapo” Guzmán to life behind bars after he was convicted on drug trafficking charges in 2019.

Prosecutors allege that Zambada and Guzmán built the Sinaloa cartel into a huge manufacturer and smuggler of illicit narcotics, bringing huge quantities of drugs into the U.S. Zambada has pleaded not guilty.

Long sought by U.S. law enforcement, he was taken into custody in July after arriving in a private plane at a Texas airport with Guzmán’s son, Joaquín Guzmán López, according to federal authorities. Guzmán López is facing drug trafficking charges in Chicago, and has also pleaded not guilty.

Since Zambada and Guzmán López were arrested in the U.S., their rival factions of the cartel have been clashing in the state of Sinaloa. This week, a dozen gunshots were fired at a building housing a local newspaper in the capital, Culiacan. The paper said no one was injured.

Separately, U.S. authorities on Thursday announced charges against a former Canadian Olympic snowboarder who they say runs a drug trafficking ring out of Mexico and is protected by the Sinaloa cartel.

During Friday’s status conference, prosecutors told the judge that some of the evidence in the case against Zambada is classified and that his defense attorneys will need clearance, according to the office of the U.S. attorney for the Eastern District of New York.

The judge scheduled Zambada’s next court appearance for Jan. 15.

In the same courthouse earlier in the week, Cogan sentenced Genaro García Luna, Mexico’s former secretary of public security, to more than 38 years in prison for taking millions of dollars in bribes to protect the Sinaloa cartel.