Nemesio Oseguera Cervantes, known as “El Mencho,” long stood among the most elusive and heavily pursued figures in global law enforcement. With a $15 million US reward on his head and as the leader of the Jalisco New Generation Cartel (CJNG), he became a central target for both Mexican and American authorities.
Mexican officials said Oseguera Cervantes was killed during a military operation in Tapalpa, a mountain village in Jalisco better known for vacation homes than cartel violence.
Intelligence derived from one of his romantic partners reportedly enabled authorities to move quickly, planning a raid on the compound where the cartel leader was believed to be hiding.
As accounts of his death circulate, here is a closer look at how El Mencho rose to become one of the world’s most wanted men.
Beginning of ‘El Mencho’
Nemesio Oseguera Cervantes, later known as “El Mencho,” grew up in El Naranjo, a rural village in Michoacán, Mexico.
Born Ruben Oseguera Cervantes, he later adopted the name Nemésio for reasons that remain unclear. His nickname “El Mencho” is believed to stem from that change, according to a report by The Associated Press.
As a young man, he moved to California in the United States. There, he married into the González Valencia family, linking him to Los Cuinis, the criminal group led by his brother-in-law, Abigael González Valencia, “El Cuini.”
After serving three years in prison for heroin trafficking, he was deported to Mexico.
Back in Michoacán, he deepened his ties with Los Cuinis, who were connected to Armando Valencia Cornelio, “El Maradona,” leader of the Milenio Cartel.
In the 1990s, Oseguera Cervantes became involved with larger trafficking networks tied to Colombian suppliers and Sinaloa-based operators. He began working as a gunman for Valencia Cornelio.
As violence escalated in Michoacán, Valencia Cornelio and the González Valencia family relocated operations to Jalisco, strengthening alliances with traffickers from Sinaloa.
From enforcer to cartel chief
Oseguera Cervantes’s rise was shaped by a succession of arrests, shifting loyalties, and fractures within Mexico’s organized crime landscape.
In the early 2000s, authorities arrested Armando Valencia Cornelio, a key trafficker tied to the Milenio Cartel.
The capture destabilized existing networks, forcing subordinates and allied groups, including members of the González Valencia family and Oseguera Cervantes — to realign.
They gravitated toward Ignacio “Nacho” Coronel, a senior operator connected to the Sinaloa Cartel and an associate of Joaquín “El Chapo” Guzmán.
At the time, Óscar Nava Valencia assumed leadership of the Milenio Cartel, which became closely linked to Sinaloa and served as an enforcement arm amid violent conflicts with Los Zetas.
But law enforcement pressure continued to redraw the map. Nava Valencia’s capture in 2009 and Coronel’s killing by Mexican forces in 2010 shattered the organization’s cohesion. Instead of weakening the drug trade, the removals deepened internal divisions, creating rival factions competing for territory and control.
Birth of the Jalisco New Generation Cartel (CJNG)
Out of that fragmentation emerged a new force. Around 2009, Oseguera Cervantes joined with Erik Valencia Salazar, alias “El 85,” to form the Jalisco New Generation Cartel, or CJNG.
What began as a splinter faction rapidly evolved into one of Mexico’s most aggressive and expansionist criminal organizations.
Over the next decade and a half, CJNG expanded across large parts of Mexico and beyond. Analysts attributed its growth partly to broader security policies and the weakening of rival cartels, particularly the Sinaloa Cartel following Guzmán’s capture and extradition. As older power centers faltered, CJNG moved decisively into the gaps.
The ascent drew escalating international attention. The United States placed Oseguera Cervantes on its most wanted lists, repeatedly increased rewards for information leading to his arrest, and later designated CJNG among major criminal organizations considered threats to national security.
Strategy, diversification, and violence
Observers say Oseguera Cervantes combined operational discipline with strategic adaptability. Under his leadership, CJNG diversified beyond drug trafficking into extortion, fuel theft, and other illicit revenue streams.
At the same time, the cartel developed a reputation for extreme violence, a tactic that both intimidated rivals and intensified government efforts to dismantle the group.
In the end, El Mencho’s rise was not defined by a single dramatic takeover. It unfolded within a turbulent environment where arrests and killings repeatedly dismantled old hierarchies and where he proved able to assemble a new, and larger organization from the fragments.
