The most-wanted cartel boss in Mexico was killed after a government operation to capture him Sunday, inciting violence across the country.
Nemesio Oseguera Cervantes, known as El Mencho, was the longtime leader of one of Mexico’s most powerful gangs, the Jalisco New Generation Cartel, and was considered one of the country’s most violent criminal figures.
The Mexican government said he had been injured during a mission led by security forces in Tapalpa — a town of about 20,000, in the western coastal state of Jalisco, where his gang was based — and died while in transport to Mexico City for medical attention.
Here is what to know about El Mencho, his cartel, and the significance of his death, in Mexico and beyond.
What is the Jalisco New Generation Cartel?
A breakaway gang that split from Mexico’s powerful Sinaloa Cartel around 2009, the cartel grew to become one of Mexico’s dominant drug trafficking organizations. It battles rivals across multiple Mexican states while moving synthetic drugs — including cocaine, methamphetamine and, in recent years, fentanyl — into the United States and other countries.
As of last year, the cartel, sometimes known by the Spanish-language acronym CJNG, was the main competitor of the Sinaloa Cartel, according to the National Counterterrorism Guide.
Oseguera, who founded and led the group, managed his cartel’s expansion by forging agreements with smaller, local gangs beyond its strongholds in the states of Jalisco, Nayarit and Colima.
The group, made up of about 15,000 to 20,000 members by American government estimates, is believed to take in billions of dollars in revenue annually. Its criminal activities include drug trafficking, extortion, fuel theft, kidnapping, illegal logging and mining, and migrant smuggling.
The Jalisco New Generation Cartel uses violence and intimidation to secure cooperation and scare off rivals. It conducts public executions and puts the bodies on display, often publicizing the violence on social media. It has also attacked and assassinated Mexican politicians, judges and law enforcement officers.
The U.S. State Department designated the cartel as a foreign terrorist organization last year.
Who was El Mencho?
The nickname is commonly used by people with Oseguera’s given name, Nemesio.
Born in 1966 in Mexico to poor farmers, he moved to California as a teenager. There, he twice faced charges of drug trafficking as a young adult. Returning to Mexico after his second arrest, he reportedly worked briefly as a police officer in Mexico.
In 1996, he married Rosalinda González Valencia, the niece of a powerful gang leader, Armando Valencia. Oseguera eventually allied himself with a Sinaloa cartel chief, and then led a splinter gang that became Jalisco New Generation Cartel.
As the new gang rose rapidly, he gained a reputation for brazen attacks on security forces and for terrorizing communities across the country. The U.S. State Department had been offering a $15 million award for information leading to his arrest.
His death was welcomed by Christopher Landau, the U.S. deputy secretary of state, who was an ambassador to Mexico in the first Trump administration. Oseguera, he said on social media, was “one of the bloodiest and most ruthless drug kingpins.”
What was the response in Mexico?
Oseguera’s killing set off a swift outbreak of violence across Mexico.
In states around the country, armed groups blocked roads and set fire to supermarkets, banks and vehicles. It was one of the most widespread eruptions of turmoil in the nation’s recent history.
The state of Jalisco said it had suspended public transportation in some areas and warned hotels to instruct their guests to remain inside. The state of Nayarit canceled classes Monday.
The U.S. government warned American citizens to “shelter in place until further notice” in parts of five states: Jalisco, Tamaulipas, Michoacán, Guerrero and Nuevo León. Airlines issued travel advisories or halted flights.
Much of the violence occurred in Guadalajara, Jalisco’s capital, a hub of 1.4 million people that is a host city for this year’s World Cup.
What may happen next?
Under President Claudia Sheinbaum, Mexico has launched its most aggressive offensive against the cartels in more than a decade.
Oseguera’s death is a major victory for the Mexican government and could help reduce pressure from President Donald Trump, who has been threatening strikes in Mexico.
But criminal empires in Mexico have a track record of outlasting the authorities’ best efforts to weaken them, and some security analysts say that the cartels are too powerful, rich and entrenched to eradicate. Even as the government showed success in efforts to fracture the Sinaloa Cartel, for example, the Jalisco New Generation Cartel appeared to gain ground.
Now, Oseguera’s killing and the violence afterward suggest that the younger gang could be in trouble.
How far the turmoil spreads may depend on whether leaders of the cartel have established a clear line of succession capable of holding the organization together. If not, Oseguera’s death could set off fragmentation and a new wave of bloodshed, according to Vanda Felbab-Brown, an expert on nonstate armed groups at the Brookings Institution.
A soldier stands guard by a charred vehicle after it was set on fire, in Cointzio, Michoacán state, Mexico, on February 22, 2026, following the death of the leader of the Jalisco New Generation Cartel, Nemesio Oseguera, known as "El Mencho." Photo: AP/PTI 
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