El Mencho Killed During Arrest Operation — Which Major Cartel Leaders Are Still At Large?

Mexico’s most powerful cartel boss, Nemesio Rubén Oseguera Cervantes — widely known as “El Mencho” and leader of the Jalisco New Generation Cartel — was killed during a security operation in the western state of Jalisco, the Mexican Secretariat of National Defence said. President Claudia Sheinbaum praised the security forces and urged calm as violent reprisals followed.

In the hours after the operation, armed cartel members launched coordinated attacks across parts of Mexico, including blocking highways and setting vehicles on fire. The operations and subsequent unrest underscore the fragile security situation and the ongoing competition among cartels to control trafficking routes and supply chains to the United States.

Cartel Leaders Still Believed To Be At Large

Zambada Sicairos

Zambada Sicairos is a senior figure in the Sinaloa Cartel’s La Mayiza faction and the son of longtime trafficker Ismael “El Mayo” Zambada. Since his father’s arrest in 2024, Zambada Sicairos has been reported to play a central role in controlling drug distribution networks and shipments bound for the United States. Spanish media report he has at least three brothers who are also involved in the cartel and who rose through the organization after starting as small-time dealers.

Fausto Isidro Meza Flores (El Chapo Isidro) [US Department of State]

Guzman Salazar

Guzman Salazar, a senior Sinaloa Cartel leader and son of Joaquín “El Chapo” Guzmán, has emerged as a co-leader of parts of the cartel since his father’s arrest in 2016. U.S. Immigration and Customs Enforcement (ICE) has said he helped orchestrate the violent response after the 2019 arrest of his half-brother Ovidio Guzmán López, in what authorities described as intense gun battles. Since 2024, his faction has reportedly been locked in a leadership struggle with Zambada Sicairos’s group, a conflict Spanish media link to nearly 2,000 deaths. Mexican and U.S. authorities are seeking him on drug-trafficking and organized-crime charges; he is believed to direct shipments of fentanyl, methamphetamine and cocaine to the U.S.

Meza Flores

Meza Flores was added to the FBI’s Ten Most Wanted Fugitives list this month, accused of heading a Sinaloa-based cartel faction. Reports say he has been detained multiple times on various charges without receiving a long-term prison sentence. U.S. authorities allege he traffics fentanyl, cocaine, heroin and other drugs into both the U.S. and Mexico and that he has been involved in kidnapping, extortion, torture and murder tied to cartel activity. The U.S. is offering up to $5 million for information leading to his arrest.

Mejía-González

Mejía-González is a long-time senior figure linked to the Gulf Cartel’s Los Rojos faction. The U.S. Department of State has announced a $15 million reward for information that leads to his arrest. According to the State Department, he is wanted for coordinating international cocaine trafficking — arranging shipments from South and Central America through Mexico into the United States. Argentine outlet InfoBae has reported allegations that his criminal activity dates back to at least 2006, when he allegedly distributed large quantities of cocaine in the U.S.; authorities also accuse him of money laundering and violent clashes with rival groups.

Why This Matters

The killing of El Mencho removes a major figure from Mexico’s criminal landscape but is unlikely to end cartel violence. Leadership vacuums often spark internal power struggles and spikes in retaliatory attacks, which can increase violence and disrupt communities on both sides of the U.S.–Mexico border. Authorities in Mexico and the United States continue to pursue remaining leaders tied to large-scale trafficking and transnational criminal operations.