A banner left at the scene of a drug war killing. Translated to English, it reads, in part, "The company does not tolerate kidnappers and traitors or anybody that acts beyond the rules."*

On December 16th, 2009, Arturo Beltrán Leyva, leader of one of the largest and most violent illegal drug enterprises in Mexico, was killed in a shootout. An ambush, really. Orchestrated by the Mexican federal government and based on intelligence from the US, it took place in a suburb about an hour’s drive south of Mexico City, as part of a coordinated assault on the upscale apartment building where Beltrán Leyva was staying. At least 200 Mexican marines were involved, along with navy helicopters and two army tanks.

Eiss calls it the narcomedia — the sharing of sometimes gruesome, terrifying messages, frequently on social media. And it’s not just the perceived bad guys sharing these messages.

The Beltrán Leyva killing is a case in point. Eiss notes that it was likely someone associated with the Mexican government who first tweeted the photo of Beltrán Leyva’s dead body. "Immediately after Beltrán Leyva’s death," Eiss writes, "someone — perhaps soldiers or forensic doctors or the masked men wearing civilian clothes who appeared in several photos of the aftermath of the event — rearranged [Beltrán Leyva’s] body, pulling his pants down and placing his body in a splayed position." Mexican and US bills were stacked and lined up on Beltrán Leyva’s body.

Images or video of carnage on social media had, of course, cropped up prior to Beltrán Leyva’s death. (Eiss points to a 2005 video leaked to YouTube depicting the torture and murder of Mexican drug cartel hit men — a leak he says was likely inspired by the YouTube-posted beheading of Nick Berg by Islamist militants.) But the Beltrán Leyva killing demonstrated how the practice had snowballed. By 2009, not only were cartel leaders sharing images of mutilated corpses on the web; their supposed rivals associated with the federal government were doing the same. By 2011, there were instances of people being killed for showing cartel allegiances on Twitter. Photos of murder scenes became commonplace. The Guardian called it a "catalog of horror."

In a conversation with The Verge, Eiss described this early stage of narcomedia as "the dark side of the Facebook revolution."

In Mexico, that dark revolution coincided, first of all, with expanded access to the web. Only 5 percent of Mexico’s population had access to the internet in 2000, Eiss’ paper points out. But by 2012 nearly one-third of Mexico’s population had Facebook accounts. Social media became the de facto form of mass communication.

The narcomedia also represents the logical progression of a drug war in an increasingly connected Mexico. As the war grew more violent in 2008 and 2009, everyone involved in the war — those representing both government and cartel interests — realized the power of social media. They realized they didn’t need newspapers or other mainstream media to push an agenda. They had their own media at their fingertips. And the messages they sent were often so powerful they motivated murder and further acts of mayhem, Eiss notes.

In the case of Beltrán Leyva, that may be exactly what happened. Six days after Beltrán Leyva’s death, gunmen murdered family members of the only Mexican marine killed in the apartment complex siege — including the marine’s mother. That same day, a fire was set at a nearby school where a banner was flown, warning that more killings would follow if the federal government made any further attempts to interfere in cartel actions. Photos of the school were then tweeted and shared in status updates — a reply to images of Beltrán Leyva’s corpse being shared on social media.

John Gibler, author of To Die in Mexico: Dispatches from Inside the Drug War, agrees that murders shared on social media represent a logical progression. "Any industry is going to use whatever it can to get their message across," he says. "Publishers create blogs, they do book promotions, post clips to YouTube, hire people to staff social media accounts. Illicit industries are doing the same — using social media in their own ways, to spread fear, and command respect and control."

Blurred lines and progress

In Mexico, the narcomedia is further complicated by blurred boundaries between those ostensibly working for government agencies and those working for cartels. "When you talk with people about these photos shared on social media, they tend to be shocked by the idea of corruption — that someone representing a government body might have been involved," Gibler says. "I urge people to reconsider this idea that the cartels and the government are two distinct entities." On the contrary, "it’s impossible for an organized crime organization — especially one that’s transnational — to function without employees inside the state at all levels."

Along those lines, Eiss references an extensive commentary in La Jornada, a major Mexico City newspaper. The commentary states that narcomedia devolved into a mere "exchange of gestures of force between formal authorities and criminal organizations, as the borders between one side and the other have blurred, due to the decay of institutions of justice and security, due to the old connections between police and kidnappers, and the infiltration of drug trafficking in the spheres of politics, business, and the media."

But as the drug war has progressed, the narcomedia has grown to encompass more than mere gestures of force.

Social media has allowed journalists and citizens to post — often anonymously — to blogs such as Blog del Narco, Nuestra Aparente Rendicion, and Borderland Beat, as well as to Twitter and Facebook, about drug war information that newspapers and other more mainstream media may be reluctant to publish. (Gibler points to the Mexican colloquialism chayote — a word meaning a payoff to a journalist in exchange for either favorable coverage or no coverage at all.) Eiss, unsure what to term anonymous drug war blogging and citizen journalism, jokingly calls it "the bright side of the dark side of the Facebook revolution" — narcomedia that serves a valuable purpose for the general public.

There's a dark side to this, too, of course (a dark side to the bright side of the dark side of the Facebook revolution). Non-journalists can be the targets of fear-mongering as well.

But in all, Eiss writes that social media has united — and made public — individuals and groups in Mexico that would’ve never publicly merged or interacted in the past. The results have been both terrifying and sometimes even inspiring. The future's uncertain.

"The rapidly changing contours of the drug war and its political entailments make further speculation about the narcomedia an exercise in predicting the future that I am reluctant to undertake," he writes. "But this much is clear: "the narcomedia have had and will continue to have profound impacts far beyond the battlegrounds of the conflict. If there is ever a declared end to that war, the narcomedia seem certain to survive it."

* Correction: a previous version of this story mis-translated the Spanish text in the opening image.