Who Is ‘El Mayito Flaco’? Anaheim-Born Ismael Zambada Sicairos, the Son of ‘El Mayo’ the U.S. Now Calls the ‘Undisputed Head’ of the Sinaloa Cartel’s Los Mayos
Ismael Zambada Sicairos, “El Mayito Flaco,” was born in Anaheim, California, in 1982 and is now the “undisputed head” of Los Mayos, the Sinaloa Cartel faction his father built. That is the U.S. Treasury Department’s description in its Sept. 29, 2026, release sanctioning him and 45 other people and companies. Here is what U.S. officials say about the son of Ismael “El Mayo” Zambada García, and what they have not proved in court.
A U.S. citizen with a changed name
Treasury describes Mayito Flaco as a dual Mexican-U.S. national. It says he filed a U.S. name change to Fernando Sicairos Aispuro in 2001. Treasury calls this an attempt “to obfuscate his cartel bloodlines.” It adds that he has been a key figure in Sinaloa Cartel operations for two decades “under his father’s tutelage.” Infobae, reporting on the release on Sept. 29, said he had appeared in U.S. court files since 2013 in connection with cocaine, methamphetamine and marijuana trafficking.
Wanted in San Diego since 2014
According to Treasury, a federal grand jury in the Southern District of California, based in San Diego, indicted him in July 2014 on drug trafficking and money laundering charges. He remains a fugitive in Mexico. On Sept. 26, three days before the sanctions, Infobae reported that the DEA had reposted his wanted notice. The notice lists him as wanted for conspiracy to distribute a controlled substance and gives Mexico as his last known location. The charges are allegations; he has not been convicted.
Heir to a cartel war
Treasury says El Mayo’s July 2024 arrest set off a “civil war” between Los Mayos and Los Chapitos, and that the two factions “remain deadlocked.” It says Mayito Flaco now directs drug trafficking, murder, extortion, corruption and kidnapping, relying on a small inner circle. The release names four members of that circle:
- Hildegardo Gastélum García, “Aldo,” described as a trusted adviser who uses a Culiacán hotel business to help finance the war;
- Jorge Luis Mendoza Uriarte, “Güero Chompas,” Los Mayos’ security chief;
- his brother Francisco Javier Mendoza Uriarte, a former secretary to El Mayo;
- Lorenzo Castillo Maldonado, who Treasury says protects Mayito Flaco, was freed from a life sentence in Mexico through bribes and hired hitmen to kill rivals in Southern California.
Treasury says the faction’s key routes into the U.S. run through Tijuana and Mexicali, across from San Diego and Calexico.
Sources
- U.S. Department of the Treasury: “Treasury Sanctions Sinaloa Cartel Leadership and Corruption Networks” (Sept. 29, 2026)
- Infobae (Ale Huitrón): “El Mayito Flaco nació en California e intentó cambiar su nombre en 2001…” (Sept. 29, 2026)
- Infobae (Miguel Flores): “La DEA vuelve a publicar ficha de búsqueda de El Mayito Flaco…” (Sept. 26, 2026)
- Photos: U.S. Drug Enforcement Administration, via Infobae (public domain); Paul Ratje/Reuters, via Infobae.
Reported Sept. 30, 2026, from the sources above. All allegations are those of U.S. authorities; Zambada Sicairos has not been convicted of any crime, and no lawyer or representative for him could be identified for comment. The number of sanction targets is as stated by Treasury.