CULIACÁN, Mexico — Bodies dumped on the side of the road. Gunbattles in upscale neighborhoods. Tractor-trailers set aflame on the highway. People plucked from their cars by armed men in broad daylight.

This is what it looks like when war breaks out within one of the most powerful criminal mafias in the world, the Sinaloa cartel, pitting two rival factions against each other in a bloody struggle to control a multibillion-dollar narco empire.

The past few years had been relatively peaceful in Sinaloa state, in northwest Mexico, where the dominance of a single, cohesive criminal organization kept turf wars to a minimum, and official homicide rates were lower than in many major U.S. cities.

Then, in late July, came an unthinkable betrayal: Ismael “El Mayo” Zambada García, a godfather of the cartel, was tricked by the son of his former ally, abducted, forced onto a flight to the United States and arrested by American agents, according to U.S. officials.

Zambada described the treachery in a letter released by his lawyer, in which the drug lord said that on the day he was arrested, he’d been lured to a supposedly friendly meeting and then “ambushed” and “kidnapped” by one of the sons of his fellow cartel co-founder, Joaquín Guzmán Loera, known as El Chapo.

It wasn’t the first time one of the capos’ families double-crossed the other. Tensions have been simmering between the two sides since El Chapo was captured and put on trial in a U.S. federal court, where one of El Mayo’s sons offered damning testimony against the drug lord in 2019 that helped put him in prison for life.

For about a month after El Mayo’s abduction and arrest, the state of Sinaloa was on edge, waiting to see whether the cartel heirs might come to a resolution. In early September, an answer came: An eruption of killings signaled the beginning of all-out civil war.

“We’re still not at the end of this long period of violence, which is overwhelming us,” said Gov. Rubén Rocha Moya of Sinaloa in an interview, adding: “The government is not overpowered at all, on the contrary, we’re increasingly better positioned to confront the violence.”

But the people of Sinaloa don’t seem to trust that anyone has control over the brutality.

Residents now follow a self-imposed curfew, sheltering inside after dark. Parents refuse to send their children to school out of fear they may get caught in gunfire. Armed men forced two local mayors out of their vehicles and stole their cars Monday, according to a spokesperson for the state’s attorney general.

Paralysis has gripped the local economy, as many employees have stopped showing up to work and businesses have reduced their hours or suspended operations altogether. The capital, Culiacán, has already suffered hundreds of millions of dollars in losses, business leaders say.

With more than 140 people killed in just one month, officials fear the violence could spread nationwide, raising the stakes for its new president, Claudia Sheinbaum.

“We are at a critical moment right now,” said Eduardo Guerrero, a Mexico City-based security analyst. “If they don’t stop what is happening in Sinaloa soon, it will become unmanageable.”

The federal government sent 1,100 soldiers to patrol the streets, and the army seized the weapons of Culiacán’s municipal police force, a move experts say reflects concern about collusion between the cartel and the local officers.

Under former President Andrés Manuel López Obrador, the government tried to avoid direct confrontations with armed groups to limit mass casualties. Sheinbaum, his protege, has vowed to continue that strategy.

“Entering with firepower would cause a war,” Sheinbaum said recently, adding that security forces must prioritize protecting civilians “but not generate more confrontation that causes more deaths.”

Before stepping down, López Obrador blamed the violence on the United States, which he said only began “because of a decision they made that was not correct and that was hatched abroad,” suggesting the U.S. government orchestrated the arrest of El Mayo.

“There was no U.S. law enforcement operation conducted in Mexico related to the arrest of Ismael Zambada García,” the State Department said.

On a recent Friday, Sinaloa police found a white van spray-painted with “Welcome to Culiacán” outside a taco shop in the capital. Crammed inside were the bodies of at least five men. When asked if the violence was slowing down, an officer exhaled sharply.

“No way,” he said, “It has just begun.”

In Elota, about an hour south of Culiacán, Rosario Salazar, 70, began taking cover as soon as caravans of armed men started rolling through town. At the sound of the heavy trucks, she and her husband would run inside their small cinder block house, turn off the lights and lock themselves in, sometimes for days.

“We wouldn’t even dare to look out of the window,” she said.

Food distributors stopped coming to town. Residents turned off their lights at 8 p.m. Salazar closed her store and started rationing food.

“We have always been poor, so we know how to adjust and live off little to nothing,” she said, “but the fear is more difficult to handle.”

Outbursts of violence have rocked Sinaloa before, but residents say this wave is more intense.

In 2019, Mexican security forces briefly arrested Ovidio Guzmán López, one of El Chapo’s sons, in Culiacán and then were forced to release him after cartel gunmen laid siege to the city.

When Guzmán López was recaptured last year, his henchmen again caused mayhem in the streets, forcing the airport and government buildings to shut down. But those episodes were over in a few days.

In southern Sinaloa, many residents remain trapped inside their homes a month after the conflict began.

“How am I supposed to feed these children?” said Luis Sapiens, a farm hand in Elota.

Sapiens, 37, normally works seven days a week in a greenhouse to provide for his wife and two daughters, 5 and 7. Now he only goes in every few days, when his boss says it’s safe enough.

The local government delivered food to his neighborhood a couple of weeks ago, but other than that, residents are fending for themselves. The local school is still shut, said Sapiens’ wife, Esmeralda, because the teachers are too scared to come to town.

She said the girls are “falling behind,” as they watched cartoons. “And there’s nothing I can do about it.”