A few weeks ago, five men were shot to death in a car repair shop in Nuevo Laredo, Mexico.
In any other city, it might be called a massacre. In Nuevo Laredo, it's called business as usual.
Across the river in Laredo, Texas, the sheriff called it something else.
"It's a war zone," said Webb County Sheriff Rick Flores. "We've got level three body armor. They've got level four. We've got cell phones. They've got satellite cell phones that we can't tap into.
"We're being outgunned," Flores added. "And that's the reason why we're concerned on this side."
The border cities of Laredo and Nuevo Laredo share four bridges across the Rio Grande, thousands of extended families and, now, the suffering caused by drug violence that, at least on the Mexico side, is out of control.
Last year in Nuevo Laredo, a city of about 500,000, the same size as Tucson, Ariz., more than 170 people were killed. Only a handful of those killings led to any arrests.
Among those slain were a city councilman, 13 police officers and the city's police chief, who had been in office seven hours when he was shot more than 50 times.
Now truckloads of federal police, similar to the U.S. National Guard, have been shipped in from across Mexico to restore some semblance of order. Last June most of the local police force was fired for being in the pockets of the drug cartels.
The federal show of force has calmed the city since a wave of particularly horrific violence last summer. But the cartels are so rich and local authorities so corrupt that no one is under any illusions that the Mexican government has them on the run. After all, they're fighting over the most lucrative drug corridor in North America, the border at Laredo, Texas.
"You have a number of the drug cartels that are in an all-out war to gain control of this area," said John Montoya of the U.S. Border Patrol. "The Laredo area is the key ingress into the United States. It's called a gateway city, not only into Mexico but into the United States as well. They use Interstate 35 to transport their illegal narcotics. They attempt to set up their infrastructure and their bases of operation not only on the Mexican side but on the U.S. side."
Each day it is estimated that more than 6,000 trucks carrying 40 percent of all Mexican exports come through Laredo. The cartels use the trucks, the warehouses and the interstate to move most of the cocaine, marijuana and methamphetamine that reaches the United States. It's a booming business worth $10 million a day, according to a senior agent at the Drug Enforcement Agency.
"By latest estimates, 92 percent of the cocaine coming into the U.S. comes in through the Southwest border," said the DEA's Rick Saldana.
The sheer viciousness of the border drug trade was made clear in a video, presumably made by one of the cartels, showing captured members of a rival gang who describe how their hit men tortured and killed those who got in their way by pouring combustibles over them and burning them with gasoline.
Saldana sees more of the same, for now.
"I think the violence will go down when one or the other cartel gets control of the area or there's a truce between the two," he said.
The area has become so traumatized with fear that the drug cartels have become the dominant institutions. They have more money, better weapons and a stronger organization than any group but the Mexican army.
The organizations that might be expected to challenge the cartels have largely given up the fight -- including the mellow new police chief of Nuevo Laredo. His predecessor, who promised to crack down, was the one who lasted just seven hours before he was killed. But Omar Pimentel, who listens to rock 'n' roll in an office painted a peaceful Caribbean blue, plans to concentrate on anything but the drug violence.
"The local police department's job is to prevent robberies," he said. "People think our job is to fight the drug cartel, but it's not."
The local newspaper, El Manana, once chased the story that so dominates its backyard. Then, one of its own reporters was gunned down. It has since backed off.
"There is no guarantee that we can do our job without getting hurt," said Anna Maria Prado of El Manana.
That leaves Raymundo Ramos, who runs a tiny human rights organization, to chronicle all the bullet-ridden bodies that turn up in taco stands, car trunks and trash barrels.
"There's a lot of fear," Ramos said. "People are more worried about personal safety than the institution."
Still, life goes on in Nuevo Laredo, which at first glance looks like any other border town. But then you notice so many of the shops are shuttered, the cafes and bars deserted, and the American tourists nowhere to be seen.
At a high-end gift shop that caters to visitors from across the border, sales are down 80 percent from the year before.
"This last year has been a devastating year for tourism for Nuevo Laredo," said Jack Suneson, a shop owner. "It's the worst we've had on record. And we've been here for 51 years. And I've never seen it this bad. We've been through floods and fires and whatnot. But this crime wave that we hit early in this part of the year has been devastating for tourism."
In fact, more residents are voting with their feet. Their homes say "vende," for sale, as they hope for a safer life across the river in the United States.
But the deadly violence from the drug wars along this border does not stop at the Texas end of the bridge.
Yvette Martinez, 27, and her friend Brenda Cisneros, 23, are among nine Americans who the FBI says have simply disappeared along the border in the last two years.
In Laredo, Martinez's mother and stepfather still wait.
"When she didn't come back, our world has been turned upside down ever since," said her stepfather, William Slemaker, who is certain Martinez was kidnapped.
Martinez and Cisneros crossed the border in September 2004 to attend a concert in Nuevo Laredo -- and never came back.
"My daughter made a phone call about 4:15 in the morning," Slemaker said. "The concert finished about 3:30, 3:40. She was about five blocks from the international bridge, coming to the U.S. to have breakfast on this side. And that's the last anybody ever heard."
"At this moment, we're just waiting for a miracle, because I'm still waiting for my daughter," said his wife, Maria Slemaker. "I want to know where she is. Even if she's not here, I have the right to know. I have the right to have her here in my hands, even if she's not alive anymore."
The unsolved disappearances have frustrated American authorities, who say they have no jurisdiction in Mexico but fear the drug cartels -- and even local police on their payroll -- are probably involved.
In the Laredo area of Texas, the crimes have even created a growing new market for kidnapping insurance.
So far, the city of Laredo has managed avoid the spectacular shoot-outs that have so devastated its sister city across the Rio Grande. But the cartels clearly don't respect national boundaries.
Just a few weeks ago, in broad daylight, a young man was gunned down in a Laredo parking lot as his pregnant wife looked on. The ambush had all the markings of a cartel hit.
What really concerns Sheriff Flores is the level of brutality that's accompanied the cartels as they move their merchandise across the border.
"What we're seeing now is that these people have no mercy for women and children," Flores said. "You know, they're just going to hose you down along with your wife and kids. We just don't know when, God forbid, we may run into some of these people. We need to be ready."
On the Texas side, inside the border patrol's Laredo station, federal agents scan the screens that monitor dozens of thermal imaging cameras along nearly 200 miles of the border. They track the ghostly images of immigrants sneaking across the shallow Rio Grande, and watch well-worn drug routes for signs of narcotics trafficking from Nuevo Laredo.
More than a thousand border patrol agents work the Laredo section, and they seize more narcotics than any other federal agency. Just outside Laredo, checkpoints along major highways, including Interstate 35, provide a second line of defense against drugs moving north from Mexico.
But the smugglers know how to slip through by using private property to circumvent some of the border patrol check stations, Flores said.
Finger Pointing and Fear
For all the beefed-up enforcement on the border, the drug cartels appear stronger and more violent than ever. Authorities on both sides of the river give lip service to better cooperation. But, in fact, they blame each other for failing to do enough to stem the drug trafficking and its deadly consequences.
Flores points to pervasive corruption on the Mexican side, where drug cartels approach poorly paid local police with offers that they dare not refuse.
"They approach you and they tell you, 'Plata or plomo?,' " Flores said. "It means, 'Money or lead? Which one do you want?' "
But in Nuevo Laredo, many Mexicans look across the river and see a never-ending American demand for illegal drugs and a willingness to spend tens of millions of dollars on the cartels that supply them.
"If I was in Laredo, Texas, I'd be embarrassed because the drug corridor is I-35 all the way to Dallas," Nuevo Laredo shop owner Suneson said. "So if this is an easy, a lucrative corridor, this means these drugs are getting across, and the United States is not doing its job. The demand in the United States, this insatiable demand that exists, is driving this frenzy over here, and that's really the problem.
The larger problem may be a combination of American demand, Mexican supply, and a culture of corruption. The unfortunate results along the Rio Grande are one city already paralyzed by fear and another deeply worried that the deadly drug violence is steadily making its way to the American side of the border.
ABC News' Chris Bury originally reported this story for "Nightline" on Jan. 5-6, 2006.