Who is El Mencho? Inside the rise of CJNG’s fallen kingpin and the cartel he built

Ruben "Nemesio" Oseguera Cervantes, known as "El Mencho," the powerful leader of the Mexican Jalisco New Generation Cartel (CJNG) who rose to prominence after the fall of Joaquin "El Chapo" Guzman, the former head of the rival Sinaloa Cartel, was killed Sunday in a Mexican military operation, authorities said. Under Oseguera’s leadership, CJNG expanded aggressively across Mexico, battling Sinaloa for control of key trafficking corridors into the United States and cementing its status as one of the world’s most formidable drug trafficking organizations. His death marks the fall of one of the most influential and elusive cartel bosses of the post–El Chapo era, long viewed by U.S. and Mexican officials as a central architect of fentanyl and methamphetamine trafficking. Deputy Secretary of State Christopher Landau said he had been informed that Mexican security forces killed Oseguera, calling it a significant victory. Mexico FLIES 37 CARTEL MEMBERS TO US UNDER PRESSURE FROM TRUMP ADMIN "I’ve just been informed that Mexican security forces have killed ‘El Mencho,’ one of the bloodiest and most ruthless drug kingpins," Landau wrote on X. "This is a great development for Mexico, the U.S., Latin America and the world. The good guys are stronger than the bad guys." A senior State Department official separately confirmed Oseguera’s death and referred to Landau’s remarks. The State Department issued a travel alert Sunday for multiple areas of Mexico , urging U.S. citizens to shelter in place due to "ongoing security operations and related road blockages and criminal activity," including parts of Jalisco, Tamaulipas, Michoacan, Guerrero and Nuevo León. TOURISTS IN MEXICAN SEASIDE CITY TOLD TO STAY ON RESORT AS GOVERNMENT WARNS OF ‘CLASHES’ Oseguera, a former police officer, helped found CJNG around 2009 after splintering from the Sinaloa Cartel. In the years that followed, the group evolved from a regional faction into one of the most dominant trafficking networks in the world. U.S. authorities steadily increased the reward for information leading to his capture, at one point offering up to $15 million, placing him among the most wanted fugitives globally. Former U.S. Drug Enforcement Administration official Paul Craine once described Oseguera as "public enemy No. 1" and said he commanded an "army of thousands." BARBARIC KILLINGS, AMPUTATIONS, RUTHLESS EXTORTION: THE ALARMING RISE OF Mexico'S Jalisco NEW GENERATION Authorities have linked him to coordinated attacks on Mexican security forces, including a 2015 assault in Jalisco in which cartel gunmen used rocket-propelled grenades to bring down a military helicopter. Over time, CJNG gained a reputation for projecting strength through public displays of force and social media messaging, reinforcing its position as one of Mexico’s most feared criminal organizations. His death removes one of the most dominant figures in Mexico’s criminal underworld and could reshape the balance of power among rival cartels.