A cartel war bleeding Sinaloa dry: Homicides rise 400% in the year after the fall of ‘El Mayo’

Police officers work a crime scene where a man was gunned down in Culiacán, Mexico. (Jesus Bustamante/Reuters via CNN Newsource)

August 10 was, for many in Mexico, a quiet Sunday like any other. But in Sinaloa – a northwestern state facing the Pacific – it was no ordinary Sunday. That day, 17 homicides were committed: one every 85 minutes.

According to Mexican government figures, it was the most violent day of 2025 in Sinaloa, exceeding every other state in the country. Sunday’s killings were some of the latest in a spate of violence that has gripped the state following the surprise arrest of Ismael “El Mayo” Zambada, who authorities say is a long-time leader of the Sinaloa Cartel, one of Mexico’s oldest and most violent criminal organizations.

Since his capture, homicides in Sinaloa have risen by more than 400%, according to an analysis of public data conducted by CNN.

This analysis also reveals discrepancies between figures compiled by the Sinaloa Prosecutor’s Office, Mexican federal authorities, and the monitoring organization Armed Conflict Location & Event Data (ACLED). Historically, Mexican authorities have underreported the number of victims during periods of violence in the region.

Even behind closed doors, U.S. defense and law enforcement officials distrust Mexico’s homicide figures, according to a source familiar with these conversations.

El Mayo’s capture on July 25, 2024, in El Paso, Texas, unleashed an internal war between rival factions, according to analysts consulted by CNN, trapping the people of Sinaloa in the middle of a conflict that has disrupted daily life, forcing large chains and family businesses alike to close their doors.

Unprecedented violence after the fall of ‘El Mayo’

The surge in violence in Sinaloa traces back to rival factions of the Sinaloa Cartel that erupted after Zambada’s capture, says Victoria Dittmar, investigator and project manager at InSight Crime.

From then, intense fighting broke out 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 to him as a real estate investment opportunity ended with his arrest in El Paso, Texas.

Zambada said 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 El Mayo’s arrest, clashes between the cartel’s factions were sporadic. But the unusual circumstances of his capture have escalated tensions.

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

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

“We have decided that the September 15 celebration will be suspended. There will be no celebration, neither public nor private,” he announced in a video posted on his X account.

Figures from that month confirm the scale of the violence: 4 deaths per day—or one every 6 hours—according to official data. ACLED reported 2 daily deaths, or one every 12 hours.

Dittmar notes that the “deceptive” way Zambada was captured not only strained relations between factions but also unleashed a wave of reprisals that has made Culiacán the main stage for an urban cartel war—something “we don’t see in any other Mexican city.”

An internal war leaves its mark on the entire community

The violence in Sinaloa transcends statistics—it has upended 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 forced to close its doors.

“There were days when there was maybe one customer, if that… because people don’t go out at night, to this day they still don’t,” says Sonia—not her real name—who spoke to CNN on the condition of anonymity, saying she feared for her safety given 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 corroborated 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 said her government was taking action: “We are working and will bring peace to Sinaloa,” she said in her daily press conference.

Nonetheless, for Sonia, that 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.”

The weak point in Mexico’s security strategy

On the July 25 anniversary, Sheinbaum reiterated the imperative for 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.

But 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.

Rocío Muñoz-Ledo, Avery Schmitz, Veronica Calderon, CNN