Despite their notoriety as such, Mexico's drug cartels aren't really drug cartels. For one, they're too busy shooting and torturing each other to collude on the kind of price-fixing arrangement that would qualify them as a proper cartel.

Nor do they deal exclusively in drugs. Over the years, many of the country's most feared criminal gangs have developed lucrative portfolios in human trafficking, kidnapping, oil bunkering and especially extortion.

What's less known is that they're also big in the news business.

In major border cities like Nuevo Laredo and Reynosa, the gangsters essentially edit the local news, which is to say, they censor it. Besieged residents of those places may witness a wild gun battle in broad daylight and see bodies splayed out in the streets, but when they pick up a newspaper the next day, they won't find a word about it.

This was not achieved by a few threatening phone calls. Over the years, the gangsters murdered, kidnapped and ran off many of Mexico's best crime reporters. They attacked newspaper offices and television studios with bullets and grenades. And while the intimidation campaign has fallen hardest on local news reporters, gunmen have also attacked and killed correspondents from Mexico's major national media outlets.

These efforts to silence and censor the news are a big reason that a new law in Sinaloa, one of Mexico's most violent states, has triggered a wave of outrage since its approval last week. State lawmakers voted for new restrictions that essentially limit reporters to covering crime and violence only after authorities have given their permission.

Under the new law, reporters will be prohibited from taking pictures or filming at crime scenes, and must wait for official news releases until publishing or broadcasting their reports. It wasn't clear how the laws would be enforced and what would happen to journalists and broadcasters who don't wait for state officials to tell them what they can cover.

"Let's imagine someone has been chopped to pieces, and the press arrives and starts taking photos, and publishing them online and in the media -- all of that is offensive to the victim's family and others," said Sinaloa lawmaker Roque Chavez, telling local reporters that the measures would improve the integrity of the judicial process and protect the work of forensic teams.

But Javier Valdez, the award-winning reporter and co-founder of the Sinaloa-based weekly Rio Doce, described the measures as a blatant attack on the press -- and one that reflects the thinking of a political class that would rather stop journalists from covering violence than stop the violence itself.

"They're more worried about the news coverage than reality," he said. "Our reality is one of murder, corruption and complicity between authorities and organized crime, and they want to cover that up for the sake of tourism and investment."

Due to take effect Oct. 15, Sinaloa's new reporting restrictions have been condemned by press freedom organizations in Mexico and abroad. Mexico's National Human Rights Commissioner Raul Plascencia called it "a bad precedent" for freedom of speech.

They are particularly galling for the Mexican journalists who have risked their lives to report on the country's criminal organizations, and who have been urging lawmakers to provide them with more protections -- not new obstacles.

Mexico ranked seventh this year on the "Global Impunity" index of countries where killings against journalists go unpunished -- the worst rating in the hemisphere -- according to an annual survey by the Committee to Protect Journalists.

After several dozen reporters staged a protest Monday in Culiacan, the state capital, Sinaloa governor Mario López Valdez said he would meet with them and that the new legislation had been poorly drafted. The backlash against Sinaloa's state legislators has been so intense that lawmakers said they will introduce a new proposal Aug. 21 to repeal the measures, blaming its approval on a busy agenda that didn't leave enough time for the fine print.

But Riodoce's Valdez said he's still skeptical. "We can't let our guard down," he said, speaking by phone from Sinaloa.

Of course, not all Mexican reporters are noble crusaders for truth and justice. Some take money in exchange for favorable coverage, or no coverage at all. Carnage-crazed tabloids tend to outnumber serious news outlets.

Yet Mexico remains a country with a fairly vibrant and mostly-free press, and one that has hung on through a dark and scary era when powerful forces from the underworld and the political world have wanted to gag it.

There were times in Ciudad Juarez in 2010 and 2011, when the city was at its deadliest, that it wasn't unusual for 10, 12 or 15 people to be slain in a single day. You could follow the local crime reporters to homicide scenes all around the city and see the bodies in the streets where they fell.

These reporters and photographers followed the police radio traffic and paid cops and others for tips, wanting to arrive first so they could get close-ups of the dead before the forensic teams got there and sealed off the area with tape.

Showing up at homicide scenes too early carried its own risks, especially when the police hadn't arrived yet and it wasn't clear whether the killing was finished. Gunmen would sometimes circle back to finish off the wounded.

Still, I never saw reporters get in the way or interfere with a crime scene. More importantly, I know that if they hadn't been there at all, there would be no way to know whether the deaths would be noted, documented and tallied, or if they'd be simply cleaned up and concealed, as if nothing ever happened, as some would have preferred.

Nick Miroff is a Latin America correspondent for The Post, roaming from the U.S.-Mexico borderlands to South America’s southern cone. He has been a staff writer since 2006.