The automatic gunfire started just after dawn in the tiny, rural town of el Aguaje, southern Mexico. More than 30 gunmen ambushed a group of state policemen out on patrol, killing 14. Walkie-talkie audio later posted on social media depicted a grim picture of the aftermath. One policeman pleads for backup as his colleague groans in pain the background. “I’m dying,” he says. Photos and TV footage of the scene showed police trucks burned out, officers dead on the ground, bits of brain on the road.

A deep dive into the drivers behind the most recent violence—in which state security forces at all levels are being outgunned, outnumbered, and outsmarted—reveals a fractured cadre of cartels more powerful than ever, facing down a weak government struggling to cope. Weapons and military training from the United States combined with the co-opting of police at all levels by cartels mean the country’s crime armies feel Mexico is theirs.

Just before the police ambush, Mexico President Andres Manuel Lopez Obrador (known as AMLO), who coined the motto “hugs, not bullets” as a way of solving Mexico’s security issues, said that the country’s brutal, drug-related violence had reached an inflection point. He was right: the decade-long crime wars had reached a tipping point, but for the worse. The police massacre and the mess in Culiacán have served to amplify AMLO’s poorly defined security strategy, and homicides have spiked since he took power in December - making a joke of his government’s attempts to enforce the rule of law.

Just a few days later, Mexico’s federal government experienced a different defeat when it attempted to arrest the son of Joaquin “El Chapo” Guzmán, Ovidio, in Culiacán, the capital of the state of Sinaloa, heartland of the Sinaloa Cartel. After initially detaining Ovidio, Mexican soldiers were forced to let him go when hundreds of cartel henchman surrounded the house in which the arrest took place. They brought the city to a standstill, burning trucks and firing on government forces. Videos showed civilian gunmen marauding around the city in pick-ups mounted with automatic weapons, firing machine guns into the streets.

Crispin Ayala Torres, a 46-year-old rancher and former resident of a town called El Limón, said that members of CJNG started turning up armed at the ranch he managed. “They tried to oblige us to fight for them, and we didn’t want to. I didn’t want to fight my own people.” He said they ran him out of town. He choked up when asked about the recent police attack. “They shouldn’t have died like that. It’s so sad, they couldn’t defend themselves.”

But local residents spoke to VICE about how criminal groups—including the New Generation Jalisco Cartel (CJNG) , which is making an aggressive bid for the state and other parts of the country—are co-opting and forcibly recruiting not just locals, but also the police that are supposed to protect them. Many locals believe the massacre was carried out because the police had refused to be bought off by New Generation. Led by Nemesio Oseguera Cervantes, a.k.a. “el Mencho,” CJNG is considered one of Mexico’s strongest cartels; the U.S. government has put a $10 million USD reward on Mencho’s head.

We answered the police’s questions and went on our way. Soon after a message went around on one of the WhatsApp groups for local police, and got to us via a local contact: “Colleagues, we report that there are a pair of foreign journalists coming from Apatzingan asking around about the gun battle in Aguililla. You already know what they’ve told us—no interviews because the bosses will get angry.”

Where were we going and what were we doing? they asked. We’re journalists, we said. It was easy to guess what story we were working on. Michoacán is now considered bandit territory by many and has been on the U.S. State Department’s no-go zone for years. Journalists were common here before, where the drug war was launched over a decade ago, but not so much these days. Armed confrontations between rival groups, police, and the military take place every day. Nearly every town is either controlled or contested by local mafias that go by names like Las Viagras , Las Mohicas (the Mohawks), and the New Michoacán Family, according to academics, journalists and local residents that spoke to VICE.

VICE wanted to find what was behind the cop killings in the humid southern state of Michoacán. A handful of officers survived the ambush in El Aguaje and had agreed to be interviewed. As we moved off the federal highway from the capital on our way to where the killings took place, we drew to a traffic stop, parallel to a state police patrol parked on the side of the road.

“Mexico is in the deadly grip of an ongoing criminal insurgency that is spreading throughout the country like a metastasized narco-cancer. It underlines the limited state capacity within Mexico and underlying corruption that exists,” said Dr. Robert J. Bunker, an adjunct research professor at the Strategic Studies Institute, U.S. Army War College.

Historically, state, municipal and even federal police and the Army can be caught up in criminal rivalries and the co-opting of police has long complicated the challenge for the government, which for more than a decade has attempted, and failed, to tackle the issue of corruption within the police forces at all levels.

This was backed up by other locals that spoke to VICE on condition of anonymity, as well as media reports . Before the massacre, CJNG had tried to get that branch of the police to work for them but the officers were already on side with another criminal cell that had long-standing community ties. CJNG is seen as such a threat by crime groups native to Michoacán that a loose pact exists between them to expel El Mencho and his men.

“It happened because the authorities are protecting some cartels and attacking Jalisco [CJNG]. I think that the ambush was vengeance,” said Hipolito Mora, a local resident who founded one of the most prominent self-defence groups in Michoacán in 2013.

Ayala said that CJNG is at war with local criminal organizations and the police who work with them, and that El Mencho’s group is frustrated because the fight for the state isn’t advancing at the rate they want. “They haven’t been able to take control [in el Aguaje].”

“In the past, the municipal police within a town could be linked to one cartel, the state police that town exists within to another cartel, and the federal police coming into that town to a third. The old adage ‘Plata o Plomo’ (Silver or Lead) is not to be discounted, for it represents the actual web of corruption and violence the cartels are weaving across the country,” said Dr. Bunker. The cop killings in Michoacán suggest that all parts of the police are now allied with organized crime. The question now is: with which group?

Police in Mexico are not only under pressure to swap their allegiance from the government to cartels, they are also seriously outgunned. This in turn makes them even more susceptible to corruption or aligning with criminal groups as a means of survival. “The Mexican police…are totally outclassed by cartel firepower and paramilitary tactics. Additionally, neither [the police of the military] is properly configured or trained to operate in a criminal insurgency environment as is taking place in Mexico,” said Dr. Bunker.

The arrival of the ferocious Zetas cartel in the early 2000s in Mexico is largely regarded as having detonated an arms race within organized crime. Founded by former Mexican military elites, they brought a new level of logistical and military training and medieval violence to the scene that other groups were forced to compete with.

But Mexico’s criminal underworld couldn’t have come to this point without the help of the United States. Not only do Americans account for the lion’s share of demand for illegal drugs from Mexico, but cartel firepower depends on the U.S weapons market. High-powered weapons (such as a .50 caliber sniper rifle) that cartel henchmen were using against Mexican soldiers in Culiacán are largely bought in the United States and smuggled south, and there are signs that the amount of weapons being smuggled south from the U.S is growing. (The expiration of the U.S. Assault Weapons Ban has also been connected to growing criminal firepower and spiking homicides.) These guns are being used to kill American as well as Mexican citizens, as this week’s slaughter of three women and six children from a Mormon community in the state of Sonora showed. All of those who died were dual U.S. / Mexican citizens.

It goes deeper than just the caliber of the weapons that the gangs are packing. Former U.S servicemen also play a role in training cartel foot soldiers, said Nick Boak, producer of a new documentary Ready for War. One of the characters in the film, called “el Vet,” was deported from the United States to Mexico and eventually ended up working for the crime lords in Ciudad Juarez, both as a killer and a trainer of other foot soldiers.