I get the first call at 4:28am on February 7. Ernesto Martinez, a 20-year veteran of the Sinaloa crime beat known affectionately as Pepis (peh-peace), tells me that there has been a gun battle in a residential neighbourhood not too far from where I am staying. I had been out with Pepis only a few hours before: at midnight the streets of Culiacan had seemed unnaturally calm and empty, as if under curfew. Pepis had dropped me off hoping to catch a few hours of sleep. He had been up the previous night reporting on numerous shootings and murders in and around the city, racing from one edge of town to the other.

It had been less than 24 hours since I had arrived in Culiacan, the capital of Mexico's Sinaloa state. Nearly six years ago I had spent time with Pepis, reporting on what life was like for Mexican journalists covering the crime beat. Now, videographer Gustavo Huerta Monroy and I had come back to see what - if anything - had changed in the city and what kinds of challenges reporters face there today.

I can barely make out what Pepis is saying - a helicopter is hovering right above his head. In a sleepy haze, I mistakenly think he says he will call back to confirm the details, so I fall back to sleep while waiting.

"Where are you guys?" It is 6:20am and Pepis is on the phone again. "There was a gun battle with the marines here, six people are dead." This time, I leave the hotel within minutes.

What I didn't know at the time is that I had arrived in Culiacan at the beginning of an upsurge in violence following the extradition of Joaquin "El Chapo" Guzman Loera, the former leader of the Sinaloa drug cartel, to the United States on January 19. More than 120 people would be murdered in Sinaloa in February, compared with an official monthly average of 92 murders over the past six years.

Speculations about soap opera-like cartel infighting were rife in the days and weeks following my visit. According to the most repeated version, Guzman's former political operator, Damaso Lopez Nunez - himself both a former Sinaloa state police chief and former vice-director of the Puente Grande prison from which Guzman escaped in 2001 - had betrayed his former boss and tried to kill two of Guzman's sons, setting off a cartel war.

It is often difficult to assess the veracity of such claims about the inner workings of Mexico's narco-trafficking organisations, particularly since murders are rarely investigated. What the surge in killings following Guzman's extradition does show is that while the demise of a kingpin as part of the "war on drugs" does little to stop the production, shipment, sale, or consumption of narcotics, it is remarkably successful at producing violent death.

"If the authorities tell you that the narcos are in retreat, that they've stopped operating, that they've suffered losses, that their organisational structure has toppled or cracked, and that their finances or money-laundering activities have been impacted, and so on … it is a lie," says Javier Valdez. I spoke with the Sinaloan investigative reporter, cofounder of local news weekly Riodoce and author of The Taken: True Stories of the Sinaloa Drug War on the day of my arrival in Culiacan.

"The strategy of decapitating criminal organisations is a failure," he continues. "Of course, it is a failure. That's why it is 'organised' crime, because they have people inside the Mexican state - people inside the governmental apparatus - working for them, because the police form a part of the criminal structure, because they have an army of hired killers, because they have financial operatives and business people - whom no one bothers, by the way - also involved. And of course there is the criminal wing, the 'capos in the shadows', who are being sought by the government in a way that ensures they will not be found."

"We haven't seen any weakening of their activities worldwide," adds Ismael Bojorquez, the director of Riodoce, speaking of the Sinaloa-based drug traffickers. "The drug shipments continue. No one has attacked their finances or the funds they operate in financial and banking networks, not only in Mexico, but in the United States and the [rest of the] world."

'Like a war'

At 6:50am Gustavo and I arrive at the Villas del Real neighbourhood where Pepis is waiting. A number of streets are closed off with yellow crime-scene tape and Mexican marines are standing guard. We find Pepis on the other side of the tape. "Wait until I walk away," he says. "And then, one by one, duck underneath the tape." We do as we're told.

A few houses down the block, a black Acura MDX has crashed in reverse into a small, pink house. Two men died here: one is lying face-down on the ground - a pistol and an AK-47 assault rifle lying next to him - the other is still in the driver's seat. The car's airbags have deployed, its tyres have blown out and the windscreen is riddled with tightly packed bullet holes.

An armoured marine truck with a mounted machinegun is parked a few metres away. It also has what appear to be bullet marks on it. The houses and cars to the right of the black car are peppered haphazardly with bullet holes. Some of the bullets travelled through the frames of parked vehicles before hitting the houses. At one house, the gunfire has pierced the walls and windows and destroyed photographs and paintings hanging on opposite walls inside the home. But somehow no one was injured there.

Pepis tells us that there had been a shoot-out between marines and armed civilians in the neighbourhood - a working-class, residential area - sometime around 3:40am. Five civilians and one marine were killed. What happened exactly is unclear and it will probably remain that way - shootings such as these rarely receive a proper investigation. The aftermath leads one to guess that a surprise meeting of marine and civilian convoys led to an exchange of gunfire and pursuit - but no more than that.

Down the street, a group of women has formed. They had all been woken by a single extremely loud sound, one of them tells me. "First it was: boom! Then: ta, ta, ta, ta, ta! It was all so loud," she says. "I don't know anything about guns. I don't know what kind they were, but it was incredibly loud. I could hear windows shattering. I thought to myself: they are shooting at the house, and started crying. But it wasn't my house."

"It was horrible," another woman standing in the group says. "Like a war," says another. "I didn't send my kids to school today," says yet another.

One woman in the group has apparently been up since the noise started. "I can't wake up, I can't finish waking up. What can I do to wake up?" she asks.

Their houses and cars shot up with high-calibre rifles, none of the local residents who I speak to has had any kind of explanation from the authorities. The on-site crime scene investigation lasts less than an hour: a state forensics team documents the positions of the vehicles, the dead bodies, guns and bullet casings. Then they take away the bodies and tow away the Acura. The marines set off in a convoy, leaving the neighbourhood unguarded.

The owners of the small pink house will have to clean up the blood on their driveway and pay for the structural repairs to their wall themselves.

A cycle of violence

It's not the first time that violence has surged in Sinaloa following a shift of power in the region's drug trade. A wave of violence between 2008 and 2011 largely corresponded to the split between two formerly allied forces. "The biggest jolts [of recent violence] have come with the re-capture of El Chapo, then his escape, and then his second re-capture in Los Mochis," says Ismael. "[These episodes] led to some movements inside the Sinaloa cartel which are now creating a significant increase in violence. Just recently some 20 people have been murdered: 12 between Saturday and Sunday, and another six this morning."

The current increase in violence is not so much due to the fall of a particularly heinous individual, however, but to the inevitable competitive restructuring of the executive level of the illicit drug trade.

It has been more than 45 years since US president Richard Nixon declared a "war on drugs", more than 35 since Ronald Reagan used that war to wage terror in the US and across Latin America and 10 years since former Mexican president Felipe Calderon echoed the US war cry to devastating human consequences across Mexico. By now, a clear pattern has emerged: each major act of war against the illegal narcotics industry has led to the restructuring, strengthening and expansion of that industry. And the expansion of the illegal industry has, in turn, been used to justify the intensification of the war against it.

"There's a negative cycle of violence and it functions as a self-justificatory cycle for the escalating drug war," Everard Meade, the director of the University of San Diego's Trans-Border Institute, who has led peace-building seminars in Culiacan for several years, tells Al Jazeera over email.

He points out that in many cases, the structural nature of drug-related violence in Mexico overrides even the best intentions of the people who enforce the country's drug policy. "The people who become the actual agents in the system - the public officials and law enforcement officers who end up making war - often begin with a less cynical and sometimes highly idealistic outlook," he says. "They come into office with high hopes of reversing the cycle of violence and not repeating the corruption and missteps of their predecessors, only to find the temptation to vengeance and short-sighted aggression irresistible."

"When men with suitcases of cash arrive at their offices and armed vehicles show up outside of their kid's school, one of their key advisers is kidnapped or killed, or they discover that half of the police force is on the payroll of organised crime, the temptation to take extreme measures is very difficult to resist," says Meade. "They imagine themselves as taking emergency measures until they can get things under control and then the emergency becomes permanent."

Meanwhile, local journalists struggle to delve into these more structural dimensions to the drug trade: "There is not much investigation into drug trafficking here. We are stuck in mediocre coverage, basically counting bodies," says Valdez. "I think we need to be telling the stories of life in the midst of all this death. But reporters keep reproducing the official line."

After the marines have left, Pepis, Gustavo and I walk down another street that has been cordoned off. Here, one marine and several civilians were killed. Thick pools of blood mark the place where each died.

Around one of the pools of blood we find the debris of care: surgical gloves, hypodermic needles, gauze, medical packaging, and a lit candle - someone had tried to save that man's life and then mourned him when he died. "This must have been the marine," Pepis says.

Residents tell me they heard the two men at the other end of the street screaming in pain, but no one had tried to save their lives. Another pool of blood lies just a few feet away behind a waist-high brick wall - possibly marking the place of death of the person who shot the marine. The location of another pool of blood around the corner tells a story of on-foot pursuit down a narrow passageway into a tiny private back patio followed by an execution against a wall.

The story of what happened this morning in Villas del Real is the story of what a high-level "war on drugs" looks like on the ground. Today six men were killed in a residential neighbourhood, authorities picked up the bodies, and towed away the dead men's car - and then left the people who live here to clean up the blood, repair their cars and homes and try to finish waking up.

Update: Javier Valdez was shot and killed in Culiacan, Sinaloa, on May 15, 2017.