Program Note: Make sure to check out Drew Griffin's full report on the flood of weapons from the U.S. to Mexico, and used by drug cartels against Mexican police on AC360 at 10 p.m. ET.
Drew Griffin and John Murgatroyd
CNN Special Investigations Unit
Some deadly dealing happens along the U.S. border with Mexico - a flood of guns, heading south, used by drug thugs to kill Mexican cops.
In Mexico, guns are difficult to purchase legally. So weapons easily purchased in the United States are turning up there.
"The same routes that are being used to traffic drugs north - and the same organizations that have control over those routes - are the same organizations that bring the money and the cash proceeds south as well as the guns and the ammunition," says Bill Newell, a special agent with the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF).
Police in Mexican border towns fear for their lives, and with good reason. Numerous high-ranking Mexican police officials have been killed recently in what Mexican officials say is an escalating war between police and drug cartels.
One of those border towns is Juarez, Mexico, just across the border from El Paso, Texas.
Juan Antonio Roman Garcia, director of the Juarez police, told us about how his colleague Cmdr. Francisco Ledesma Salazar was gunned down in front of his home.
The weapon used to kill Salazar is believed to have been a .50-caliber rifle. The guns are illegal to purchase in Mexico but can be obtained just north of the border at gun shows and gun shops in the United States.
"This is done with one single purpose, to weaken the police structures and create fear in the lower officers," Roman Garcia told us in an interview last year.
Two months after the interview, Roman Garcia himself was killed in front of his home after narco terrorists sprayed the vehicle he was driving with bullets fired from an AK-47.
ATF special agent Tom Mangan says the .50-caliber rifle, like the one believed to have been used to kill Salazar, has become one of the "guns of choice" for the drug cartels. The weapon fires rounds the size of the palm of your hand that can cut through just about anything.
Mangan showed CNN the power of the rifle on a gun range near Phoenix, Arizona. The weapon, a Barrett, was seized in an ATF raid. A round fired from 100 yards away tore through a car door and both sides of a bulletproof vest like those used by Mexican police.
"There's nothing that's going to stop this round," Mangan says.
The rifle was intercepted as it was being smuggled into Mexico. Mangan says investigators believe four others already had passed through the border.
The ATF has been trying to help Mexican police by cracking down on illegal purchases of guns and ammunition. Operation Gunrunner has led to several arrests and seizures of guns and ammo. But the operation has mainly shown just how big a problem exists, authorities say.
A single seizure in a Yuma, Arizona storage locker last year yielded 42 weapons and hundreds of rounds of .50-caliber bullets already belted to be fed into a machine gun-style weapon.
The guns confiscated included AK-47 rifles and dozens of Fabrique National pistols. The semiautomatic pistols fire a 5.7-by-28 millimeter round, which is technically a rifle round, according to the ATF. Newell says the round has a special nickname in Mexico. "It's called 'mata policias,' or 'cop killer,' " he says.
Guillermo Fonseca, Mexico's regional legal attaché for the West Coast, told CNN the violence in his country is "problem number 1" - and police in his country are outgunned. With large-caliber weapons from the United States, drug cartels and criminals have a big advantage in what he says is war. Part of the solution, he says, is for the United States to give Mexico more information about who is selling these guns illegally in the United States. Then Mexico could go after the buyers.
"We have access to systems to trace guns that have been smuggled into Mexico, and that has worked very well," Fonseca told CNN. "We need more information about the people who are actually purchasing the guns. We need to prosecute those people, to convict those people."
Officer Cesar Quitana patrols a dangerous barrio in Juarez, Mexico. He is armed with an M16 assault rifle - sounds big, right? But it would be no match in a gunfight with drug lords.
"I think most of us feel scared just to bring this with us," he says, pointing to the rifle in the front seat of his patrol car. "But this is what we use to defend ourselves."