A powerful Mexican drug cartel leader on Thursday made his second appearance in federal court in Texas after being taken into U.S. custody last week.

Ismael “El Mayo” Zambada, 76, used a wheelchair for the hearing before U.S. District Judge Kathleen Cardone in El Paso. Zambada, the longtime leader of Mexico’s Sinaloa cartel, eluded authorities for decades until a plane carrying him and Joaquín Guzmán López, a son of notorious drug kingpin Joaquín “El Chapo” Guzmán,” landed at an airport near El Paso on July 25. Both men were arrested and remain jailed. They are charged in the U.S. with various drug crimes.

Discussions during the short hearing Thursday included whether Zambada would be tried with co-defendants or separately. He is being held without bond and pleaded not guilty during a short hearing last week, where he also used a wheelchair.

His next hearing date was set for Sept. 9. His attorneys declined to comment after Thursday’s hearing.

One of his attorneys, Frank Perez, previously has alleged his client was kidnapped by Guzmán López and brought to the U.S. aboard a private plane. Guzmán López, 38, pleaded not guilty Tuesday to drug trafficking and other charges in federal court in Chicago.

Zambada was thought to be more involved in day-to-day operations of the cartel than his better-known and flashier boss, “El Chapo,” who was sentenced to life in prison in the U.S. in 2019.

Zambada is charged in a number of U.S. cases, including in New York and California. Prosecutors brought a new indictment against him in New York in February, describing him as the “principal leader of the criminal enterprise responsible for importing enormous quantities of narcotics into the United States.”

The capture of Zambada and Guzmán López has fueled theories about how federal authorities pulled it off and prompted Mexican President Andrés Manuel López Obrador to take the unusual step of issuing a public appeal to drug cartels not to fight each other.