|Drug-related violence has made Mexico one of the world's most dangerous countries for journalists [AFP]
The bodies of two young people have been found hanging from a bridge in northern Mexico accompanied by a hand-lettered sign warning social media users from reporting on violence.
The corpses of a young man and woman, dangling from a pedestrian walkway in the city of Nuevo Laredo near the US border, showed signs of torture and were badly mutilated, an official at the state prosecutor's office said on Tuesday.
"Watch out, I've got my eye on you," the placard said, according to photos from the scene, warning that the same would happen to all "scandal mongers" on the internet.
The placard was signed "Z", a reference to the Zetas, a notorious drug gang that operates in the area.
The victims, who have not been identified, were aged between 20 and 25, said the official, who asked not to be named. Al Jazeera could not confirm if they were social media users.
Two popular websites covering the Mexico drug war, Blog del Narco and Frontera al Rojo Vivo, were mentioned and threatened on the placard.
The Rojo Vivo site, managed by border newspaper El Norte, said all archived material had been cleared from the blog, removing information about contributors.
"From now on, we will only publish specific facts and information about border communities and not personal attacks," read a notice on the site on Thursday.
Wave of fear
Quoting police investigators, Al Jazeera’s Frank Contreras, reporting from Mexico City, said: "The two victims were not journalists but people from the local community. They were using social media to denounce crimes.
"The messages here from criminal organizations is that if you try to denounce organized crimes members who commit violent deaths, you too could become a victim."
Our correspondent said the deaths have started to send a wave of fear across social networks, where people have been denouncing crimes. "That is because in Mexico, in some places where drug-related violence has been raging, news media organisations are not covering the stories," he said.
"They prefer self-censorship as a way to protect journalists. And so it has fallen on the citizens themselves to report these crimes using social media networks."
Drug-related violence now makes Mexico one of the world's most dangerous countries for the press, where drug traffickers often target local media and try to suppress coverage, according to the Committee to Protect Journalists (CPJ).
CPJ says that at least 42 local reporters have been killed over the past five years.
In July, it published a report saying that 15 journalists have been killed since 2010, at least four in direct reprisal for their work.
Many newspapers and other media have stopped publishing graphic photos of murder victims or the calling cards that drug gangs use to threaten rivals, the police or public.
Mexico has become the battleground for brutal turf wars between the Zetas and other drug cartels. Around 42,000 people have died in Mexico's drug wars since President Felipe Calderon took office in 2006.
Calderon has deployed the military onto the streets to take on the cartels.