Mexico is investigating whether U.S. agencies violated its sovereignty during the 2024 capture of Ismael “El Mayo” Zambada, one of the most powerful figures in the Sinaloa Cartel. The El Mayo Zambada investigation has renewed tensions between Mexico and the United States over cartel enforcement and cross-border operations.
Mexican officials said the inquiry focuses on whether any U.S. agency participated in the operation that brought Zambada into American custody. The case has drawn new attention after the FBI displayed the plane allegedly used to transport him to the United States.
El Mayo Zambada Investigation Raises Sovereignty Questions
Mexican President Claudia Sheinbaum said Tuesday that any U.S. agency involvement could violate international agreements and Mexico’s constitution.
Zambada was arrested in July 2024 in the United States alongside Joaquín Guzmán López, a son of imprisoned Sinaloa Cartel co-founder Joaquín “El Chapo” Guzmán. At the time, questions quickly emerged about how Zambada, who had evaded authorities for decades, ended up in U.S. custody.
Mexican officials have said the U.S. Embassy in Mexico previously denied that U.S. agencies participated in the operation. Mexico’s government is now reviewing that account against newer information.
Rosa Icela Rodríguez, Mexico’s security secretary, said the versions do not match. “Someone lied,” she said, according to reports.
Alleged Kidnapping Central To The Case
The controversy intensified after Guzmán López pleaded guilty to U.S. drug trafficking charges. As part of that case, he admitted that he kidnapped Zambada and brought him to the United States.
According to details cited in court-related reports, Zambada was ambushed, put on a plane, drugged and transported across the border. That alleged sequence has become central to Mexico’s investigation.
The main question is whether U.S. authorities only received Zambada after the flight landed, or whether they helped plan or support the operation. Mexican officials have not publicly presented a final conclusion.
Sheinbaum also questioned what agreements may have existed between any agency and members of a criminal group. Her comments suggest the investigation could become a broader review of U.S.-Mexico security cooperation.
Who Is El Mayo Zambada?
Zambada is one of the longtime leaders and co-founders of the Sinaloa Cartel. U.S. prosecutors have described the cartel as a major trafficking organization responsible for moving fentanyl, cocaine, heroin and methamphetamine into the United States.
In August 2025, Zambada pleaded guilty in U.S. federal court to charges tied to a continuing criminal enterprise and racketeering. The U.S. Department of Justice said he helped lead one of the world’s most powerful drug trafficking organizations.
His capture also deepened internal violence in the Sinaloa Cartel. Reports from Mexico have linked the arrest to conflict between rival factions connected to Zambada and the sons of El Chapo.
Diplomatic Tensions Continue
The investigation comes as Mexico and the United States continue to clash over how to confront cartels. Washington has pushed for more aggressive action against criminal groups, while Mexico has repeatedly defended its sovereignty.
Sheinbaum has said Mexico will cooperate with U.S. authorities on security matters. However, her government has also insisted that foreign agencies must respect Mexican law.
The case now places both governments under pressure to explain what happened in 2024. For communities affected by cartel violence on both sides of the border, the outcome could shape future cooperation in the fight against organized crime.