U.S. Guns Behind Cartel Killings in Mexico

Arizona and Texas have become a "gunrunner's paradise," according to Garen Wintemute, a professor at the University of California at Davis who published a study on gun buying in the Southwest. Licensed dealers must conduct background checks, but unlicensed sellers can sell "personal collections" at weekend gun shows without background checks.

Laws on personal collections were established to allow people such as the widows of avid gun collectors to make sales without having to go through an elaborate licensing procedure. But unscrupulous sellers and buyers have taken advantage of the system, Newell said, setting up phony personal collections booths and making quick sales that are difficult to trace.

"It can take less than a minute," said Wintemute, who has watched unlicensed dealers wearing sandwich boards at gun shows and piling weapons for sale into baby carriages.

Authorities have tracked smugglers who bought dozens of weapons at various shows in a single weekend. The guns are often purchased by middlemen, or straw purchasers, who sometimes get on-the-spot instructions by cellphone from Mexican drug traffickers. The straw purchasers often live in the United States, either legally or illegally.

A smuggler, or ant -- often the same person who bought the guns -- then slips the weapons into car trunks or false vehicle floors. Among the new weapons of choice for Mexican drug dealers are so-called variants of AK-47s and AR-15 assault rifles, which are shorter than standard models and can even be concealed in baggy pant legs, Newell said.

As in the drug trade, young women are often recruited as weapons smugglers, Newell said, because they are less likely to be targeted by inspectors. Smugglers frequently work in teams, he said, distracting border inspectors by dispatching a man "who looks like he just got out of prison" to stand in front of a young woman carrying a baby and hidden weapons.

"She looks cute and she's nicely dressed," Newell said. "While they're checking the guy, the young girl glides right through."

But some smugglers don't need to bother with diversionary tactics.

Jorge Gonz¿lez Betancourt, president of the national defense committee in the lower house of Mexico's Congress, acknowledged in an interview that "corruption in the customs system" allows guns and drugs to transit Mexico. The customs agency is coming under greater scrutiny, especially since the recent arrest of the head of inspections at the port of Altamira, north of Tampico, who is accused of letting 12 tons of cocaine enter the country.

In August, Mexican authorities in Nogales, across the border from Arizona, seized 163 weapons in one of the largest busts in recent Mexican history.

Mexican customs officials say they can inspect only a tiny fraction of the 65,000 vehicles and 35,000 pedestrians that each day cross the border at Tijuana, a city where countless underage Californians have flocked for generations to drink and carouse.

Piles of guns make it through, many ending up in the hands of Tijuana's powerful drug cartels. But other weapons bounce farther south, creating what V¿ctor Manuel Zatara¿n Cedano, the Tijuana police director, called the city's "trampoline" effect.