Zambada's lawyer Frank Perez has also represented his son, Vicente Zambada Niebla, who prosecutors say could testify against him at trial. Zambada Niebla previously testified against Joaquin "El Chapo" Guzman, who founded the notorious Sinaloa Cartel alongside Zambada.

U.S. prosecutors said Wednesday that they're discussing a potential plea deal with Ismael “El Mayo” Zambada, the long-elusive Mexican drug lord who was arrested last summer and whose son could testify against him if he goes to trial.

Ismael "El Mayo" Zambada decided to stick with the lawyer defending him from U.S. drug trafficking charges despite a possible conflict of interest.