Sinaloa Cartel Internal War Erupts After Arrest of Ismael El Mayo Zambada, Causing Historic Violence and Disruptions in Daily Life

On August 10, 2025, an extraordinary episode of violence unfolded in Sinaloa, a northwestern Mexican state. The day witnessed seventeen homicides, occurring approximately every 85 minutes, marking it as the most violent day in the region that year.

According to official statistics, this surge in violence followed the arrest of Ismael “El Mayo” Zambada, a long-time leader of the Sinaloa Cartel, one of Mexico’s oldest and deadliest criminal organizations. The spike in homicides has risen by over 400% since his capture, as per an analysis of public data conducted by CNN.

Discrepancies exist between the homicide figures reported by the Sinaloa Prosecutor’s Office, Mexican federal authorities, and monitoring organization Armed Conflict Location & Event Data (ACLED). Historically, Mexican authorities have been criticized for underreporting violence during periods of unrest in the region.

Even behind closed doors, U.S. defense and law enforcement officials express skepticism towards Mexico’s official homicide statistics.

Zambada’s arrest on July 25, 2024, in El Paso, Texas, reportedly initiated an internal war between rival factions of the Sinaloa Cartel. This conflict has disrupted daily life in Sinaloa, forcing large chains and family businesses to close temporarily.

The increase in violence can be traced back to the power struggle that erupted within the Sinaloa Cartel following Zambada’s arrest, according to Victoria Dittmar, investigator and project manager at InSight Crime.

Intense fighting ensued between his followers—known as the Mayitos—and allies of Joaquín “El Chapo” Guzmán, punctuated by sustained clashes between smaller Sinaloa Cartel factions. This trend is reflected in ACLED’s data.

In a statement released by his lawyer, El Mayo claimed he was deceived by one of El Chapo’s sons and a leader of the Sinaloa Cartel himself, Joaquín Guzmán López, who lured him to the United States under false pretenses. According to Zambada, the meeting pitched as a real estate investment opportunity ended with his arrest in El Paso, Texas.

Zambada asserted in his letter that he was tricked, kidnapped, and handed over to US authorities by Guzmán López—an account the latter denied through his legal team, which has also rejected the idea that El Chapo’s son voluntarily surrendered.

Both men face multiple charges in the U.S. Eastern District Court of New York, where they have pleaded not guilty.

Before Zambada’s arrest, clashes between the cartel’s factions were sporadic. However, the unusual circumstances surrounding his capture have escalated tensions significantly.

Now, both the Mayitos and Chapitos have stepped up their offensives to seize key territories, as per Dittmar’s analysis. ACLED data shows a sharp increase in violence in early September, when analysts agree the war officially began.

To ensure the safety of students in Sinaloa, Governor Rubén Rocha Moya ordered classes canceled on September 12 and 13. The following day, amid the insecurity, Independence Day celebrations were suspended in several towns across the state—including in the capital of Culiacán.

Data from that month reveals the scale of the violence: an average of four deaths per day or one every six hours, according to official data. ACLED reported two daily deaths, or one every twelve hours.

Dittmar notes that the “deceptive” nature of Zambada’s arrest not only strained relations between factions but also unleashed a wave of reprisals that has made Culiacán the epicenter of an urban cartel war—something unprecedented in any other Mexican city.

The violence in Sinaloa exceeds statistics, upending residents’ daily lives. In Culiacán, the constant fear of armed clashes has forced large chains and small family businesses to reduce their hours or shut down completely.

One small business owner, who operated her grandmother’s decades-old restaurant in the Sinaloan capital, was compelled to close its doors. “There were days when there was maybe one customer, if that… because people don’t go out at night, even today they still don’t,” says Sonia—not her real name—who spoke to CNN on the condition of anonymity, fearing for her safety due to the city’s insecurity.

Like many others in Culiacán, Sonia and her family have had to adapt to a new normal, imposing a self-curfew. “We, the citizens, decided months ago to only go out at certain times,” she explains. “At first, between September and December, it was like a self-imposed rule because you were afraid to go out. Normally, nights and early mornings were most violent… but really, the whole day is. You can go out at noon and get caught in a shootout leaving a school, on a main street, between police, soldiers, marines, and gunmen. Just like that. That’s the reality every day.”

Videos shared on social media and verified by CNN illustrate scenes that have become increasingly common in Culiacán and other cities across the state: shootouts in broad daylight, clashes between armed groups and security forces, and burning vehicles in residential neighborhoods.

Footage shows that the clashes have largely occurred in urban areas—a new trend that, according to Dittmar, has exposed hundreds of thousands of people who, previously, were not directly impacted by the conflict.

Some of these violent incidents have taken place near Sonia’s restaurant, she says; CNN confirmed her claim using open-source data.

In May, the body of a man was found hanging from a nearby bridge alongside a narco-message; a month later, a human head was left near a tourist site in Culiacán; and two weeks after that, several police officers were seriously injured in a nearby ambush.

On the first anniversary of El Mayo’s arrest, Mexican President Claudia Sheinbaum stated that her government is taking action to bring peace to Sinaloa. However, for residents like Sonia, this promise feels distant: “You see military convoys everywhere, but there’s no real strategy. There are areas where there are shootouts every day and the authorities arrive hours later. It’s all for show. We’d like to see a real strategy… because there isn’t one.”

On the July 25 anniversary, Sheinbaum reiterated the importance of collaboration with US authorities and warned against foreign interference in countering cartel-linked violence and trafficking in Mexico.

Her comments came days before US President Trump signed a secret directive instructing the Pentagon to use military force against certain cartels in Latin America that his administration had designated as foreign terrorist organizations, according to a New York Times report.

While it remains unclear whether the US Defense Department intends to coordinate its efforts with Mexican authorities, the Sinaloa Cartel is one of eight criminal networks designated as foreign terrorist organizations by the Trump Administration.

In the first year of her administration, ACLED data shows, Sheinbaum’s efforts to contain violence have generally coincided with a drop in attacks against civilians; since January, civilian killings have declined in nearly every Mexican state.

However, Sinaloa remains, without a doubt, the weak spot in Mexico’s security strategy, with at least 571 civilians killed there in 2025 so far. (In three other states where civilian homicides have increased, the combined total is 49 victims, through July 25).

Targeted killings of civilians have already surpassed the total recorded for all of 2024, setting the stage for this year to be one of the deadliest in Sinaloan history. And for many in Sinaloa, that August Sunday was yet another reminder of the raging war with no end in sight.