The Mexican drug cartels silenced the mainstream media by threatening and killing journalists. Now they seem to be extending the practice to social media.

Many Mexicans have had to rely on social media to find out what’s going on in their cities after newspapers, TV and radio stations stopped reporting on drug-related violence.

But last week, the mangled bodies of a young man and woman were hung from a highway bridge in Nuevo Laredo along with a sign that read: “This is what happens to people who post funny things on the internet. Pay attention.”

People are paying attention.

“It suggests that the blogosphere has been included in the media landscape that the cartels are looking at. Because up until now it has only been traditional media —print, TV and radio,” Javier Garza is the editor of El Siglo de Torreon, a newspaper in the neighboring Coahuila state, which is also aflame with cartel violence.

A New Battleground

The message seems to indicate that a drug cartel is upset that its activities are being posted on websites — two in particular.

Frontera Al Rojo Vivo – loosely translated as The Raw Border – is a blog run by a newspaper in Monterrey for use by border residents.

The other is Blog del Narco, a notorious website run by an anonymous webmaster and open to anyone. Blog del Narco accepts posts from ordinary citizens, police agencies, and, increasingly, the narcos themselves. The site features grisly photos and videos of cartel mayhem around the country.

And the narcos want it both ways. They want to censor the negative things that people say about them on this and other blogs. And yet they want a forum to post their own propaganda, or have sympathizers do it on their behalf.

Blog del Narco has become just that, according to Rosental Alves, a journalism professor at the University of Texas at Austin who follows new media in Latin America.

“In Blog del Narco (they) are amplifying the public relations efforts the cartels had already started,” he said.

In the routine barbarity that defines the Mexican mafia, they use images of murder, torture and even beheadings to intimidate foes and brag of their exploits.

Blog del Narco, like the popular Mexican tabloids, has learned that savagery sells. You can log on, and see photos of severed heads and disfigured bodies next to ads for GM Truck Month, Geico Auto Insurance, and Lysol Toilet Bowl Cleaner.

Web Activities Provide Intelligence

On another level, Blog del Narco and copycat websites have become required watching for intelligence gatherers who want to know what the cartels are up to.

“Some traffickers have been tortured on film and they recite a lot of useful information, information about command and control, information about sponsorship of killings, the list is endless,” said a spokesperson for Grupo Savant, a private security firm in the Washington, D.C. area with knowledge of organized crime activities in Mexico. The spokesperson requested anonymity.

This is not to say that all social media in Mexico has been co-opted by drug traffickers.

Some networks do provide timely information for nervous citizens. Twitter followers of #nuevolaredo will ask: Does anybody know what the boom heard downtown was — a harmless firecracker or a hand grenade?

But, increasingly, experience tells Mexicans to be cautious about the information they get on social networks.

“We’ve seen infiltration by criminal groups who use social media to spread rumors that can create mass psychosis,” says a veteran journalist in Matamoros, who asked not to be named. “Far from calming people, it just makes them more panicked.”

False Information Causes Chaos

There have been instances, for example, in which cartel members tweet about a shootout in a certain neighborhood for the purpose of diverting the police and miltary to that area. Then the cartel unleashes an operation in another part of the city.

And some of the misinformation comes from well-meaning citizens.

Veracruz is a port city on the Gulf of Mexico that’s being contested by warring mafias. Weeks of running gunbattles have put the city on edge.

This week, gunmen in two trucks dumped 35 bodies of suspected rival gang members onto a busy avenue. Horrified motorists frantically tweeted for others to avoid the area.

That was real.

But a month ago, two residents independently tweeted that narcos were kidnapping children from schools. Bedlam broke out. Parents raced through the streets to the schools to rescue their children. Police logged 26 vehicle accidents.

It was a false alarm.

“If you tweet false information about violent episodes, I think first we have to discern your intent — is it malicious intent or did you just retweet information you saw elsewhere?” said Javier Garza, the newspaper editor.

Initially, angry state prosecutors arrested the two Veracruz residents who tweeted and charged them with terrorism and sabotage. But human rights and internet freedom activists screamed foul.

This Wednesday, authorities dropped the charges against the two and they walked out of jail to jubilant supporters. The Veracruz state legislature is now expected to create a new offense for bloggers who “disturb the peace.”

Copyright 2011 National Public Radio. To see more, visit http://www.npr.org/.