Reporters have protested impunity and corruption which allow gangsters to kill the messengers [EPA]

 Pedro Torres doesn't have the air of a man who stares down death on a daily basis. He is a mild mannered reporter during the day, and at night.
But just showing up for work at El Diario newspaper in Juarez, one of the world's most dangerous journalism jobs, could be considered a heroic feat.
"This is what I like to do, I have been here for 25 years," Torres says during an interview in his office.
It's a standard answer for a newspaper man, except that two of his staff members have been gunned down in cold blooded shootings in the last few years, as drug violence rages in this border city.
The desk where Armando "El Choco" Rodriguez once sat - writing tracks on crime and government corruption -has been left vacant as a shrine after he was murdered in a targeted killing in November, 2008. He was sitting in his white Nissan car, preparing to drive his daughter to school, when masked gunmen approached, opened fire with automatic weapons and then fled. No one has been prosecuted for the attack.
"Journalists are being killed systematically and regularly," says Bruce Bagley, chairman of the international studies department at the University of Miami, who researches Mexico. "Narco groups have decided they don’t like bad publicity in the areas which they control; it has become incredibly dangerous to be an investigative reporter. Often, local and state police are complicit in these attacks."
A few days before his murder, Rodriguez had written a story linking the state prosecutor's nephew to drug traffickers. Cartels earn as much as $39bn yearly from selling illicit narcotics, according to the US Justice Department, and serious journalism which exposes criminality is bad for business.
Cartels as 'de facto authority'
Between December 2006, when Mexican president Felipe Calderon declared an all-out war on cartels, and May 2011, 44 journalists have been killed, according to a report by the Mexico’s National Centre for Social Communication.
The International Press Institute says 12 journalists were killed in Mexico in 2010, second only to Pakistan with 16.
Mexico is facing one of the world's most radical declines in press freedom, as journalists are killed and intimidated and newspapers are forced to publish press releases from criminal groups as if they were pure news, according to the 2010 Press Freedom Index released by Freedom House think-tank in May 2011.
"If journalists want to continue to work, they have to avoid certain topics," says Celeste Bustamante, a professor of journalism at the University of Arizona who studies violence and the media in Mexico. Local reporters in the country’s north, where cartels battle for transit routes into the US, are in the worst situation, she says.
"A lot of the information about the drug war is coming out in books and blogs, and not necessarily where you would typically find it," Bustamante says.
More than 36,000 people across Mexico have been killed in drug violence since 2006. Luis Carlos Santiago, 21, a photographer for El Diario, was one of them. He had just started work and wasn't even covering the drug war when he left the newsroom one autumn afternoon with Carlos Sanchez, another photographer, to get some lunch. Gunmen in two vehicles intercepted Santiago and opened fire on his car, killing him and seriously wounding Sanchez. 
After the young photographer's murder in September 2010, Pedro Torres and his fellow reporters responded the only way they knew how: With their words.
"It is impossible for us to do our job under these conditions," the editors wrote in a bold front-page editorial addressed to drug cartels. "We ask you to explain what you want from us, what we should try to publish or not publish, so we know what to expect," they wrote, calling cartels the "de facto authority in the city".
"The loss of two reporters from this publishing house in less than two years represents an irreparable sorrow for all of us who work here, and, in particular, for their families," the newspaper said.
The editorial made headlines around the world. It infuriated local politicians, who accused the newspaper of caving to criminals. "I think the editorial was a primal scream or a form of existential despair,” says Bagley. "How do our people cope with this situation?"
Like thousands of brave Mexican journalists, Pedro Torres, who helped pen the editorial, keeps reporting but thinks the situation is "getting worse".
Massacres
While the killings in Juarez, of journalists and everyone else, have drawn international attention, the situation is likely more dangerous in neighbouring Tamaulipas state.
"In 2010, with the massacre of 72 migrants in Tamaulipas, we [researchers] started to notice that we didn’t know what was happening there," says Guadalupe Correa-Cabrera, a professor of government at the University of Texas in Brownsville, which borders Tamaulipas. "People from the region were, of course, aware of this [violence and corruption], but they were terrified."
Graves with nearly 200 bodies have recently been discovered in the state, where shoot-outs between security forces and gangsters are commonplace. "We saw almost nothing [in the local press]. We heard about these things [happening by informal media, the narco blog, borderland beat, and social networks," Cabrera says.
Drug cartels in the underdeveloped, and primarily rural border state, operate as if they were paramilitaries, similar in tactics to forces fighting in Colombia in the late 1990s or Guatemala and El Salvador during the Cold War.
"People use twitter to keep up with these events," Cabrera says, adding that most people, especially in rural areas, aren't online.
"The digital divide is huge," Celeste Bustamante says. But even with low rates of internet penetration in key regions for journalists in the US and researchers around the world who want to understand the violence, social media is often one of the only options.
For journalists, the lack of formal sources, in addition to violence, makes reporting difficult as citizens who witnesses (or commit) crimes won't talk on the record. Cabrera, for example, does most of her academic research through "social media and informal sources".
"Everything is based on an aspect of speculation," she says. "We don't know how many people are killed on any given day; we have to build a story through informal sources." This is a problem, media activists say. Violence means people need local news more than ever, and that is exactly what they are not getting from traditional media.
'Can anyone confirm'?
Using the hash tag #reynosafollow, a twitter user called gromerog reports (in Spanish) that: "There's like 9 trucks with armed people at the entrance of delnosa at arachina south."
The idea that citizens would use twitter to report this kind of information or to "decide whether it is safe to send the kids to school on a given day" would have been unheard of five years ago, Bustamante says.
But the conflict is changing Mexico, technology is changing journalism and the confluence of those factors has led to the emergence of a social media movement, where anonymous citizens are trying to help each other navigate an increasingly brutal terrain.
"Did a grenade explode at a police station in santa catarina, does anyone know anything, can confirm?" a distraught twitter user called KrizzCortes asks from Monterrey, Mexico's commercial capital. 
"Juarez, Nuevo Laredo, Tijuana, and Reynosa [the major city in Tamaulipas state] have all developed these networks saying, 'don't go to Third Avenue because they have just found a burning car with all these bodies',” says professor Bagley. "We have also seen the use of Facebook to organise protests" against violence and militarisation.
In early May, tens of thousands of people rallied across Mexico, under banners reading "this government is driving us down to hell" and "this is not our way but these are our dead" likely referencing drug consumption in the US.
Despite the threats faced by journalists, Javier Sicilia, a poet and magazine columnist, has played a leading role in organising protests since the slaying of his 24-year-old son.
But it is not just the families of slain journalists and their co-workers who suffer. Mexico is considered a transitional democracy; the Institutional Revolutionary Party (PRI) ruled the country for 71 years until voters managed to turf them from office in 2000. And serious journalism is most needed in societies with weak institutions. If journalists cannot expose corruption, and the police and judges are in the pockets of cartels, then the vicious cycle will continue.
"The flow of information has been severely constrained," says Bruce Bagley. "There has been less and less effective reporting."
While Mexican media outlets have been criticised for their coverage, American outlets - who are not dealing with violence - have also faced scorn for their approach.
"My biggest disappointment is that we in the US media don't do enough on the demand side [of drugs]," says Nuri Vallbona, a former Miami Herald photojournalist who has covered Mexico. "We don't talk enough to people who do drugs. There is a disconnect; they [consumers in the US] don't see how their behaviour is causing this violence."
Follow Chris Arsenault On Twitter: @AJEchris