X-rays lead to startling human cargo bust

LOS ANGELES - CBS News correspondent Bill Whitaker reports a disturbing case of human smuggling has been uncovered in Mexico.

More than 500 people were found packed into two trucks in Mexico's southern most state. They were enduring unthinkable conditions to get to America. But they still had close to 1,000 miles to go.

The 513 migrants, hot, tired and dehydrated, were rounded up and processed for detention in Chiapas, Mexico, shortly after two trucks smuggling them across the border tried to blow past a security checkpoint.

Authorities were alerted to the human cargo by an amazingly detailed X-ray, showing people sittings, standing and jammed into the trucks.

The 240 people in one truck and 273 in the other were packed so tightly -- up to seven people per square yard -- that they could barely move or breathe.

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The temperatures inside topped 100 degrees. More alarming, they came from at least eight different countries: 410 from Guatemala, others as far away as India, Nepal and China - a smuggling pipeline run by gangs.

"We're talking about something that's far more systematic than people realize," says Demetrios Papademetriou, of the Migration Policy Institute. "They learned how to do this by trying to move drugs and other contraband.

After the Golden Venture, carrying 286 Chinese nationals, ran aground off New York 18 years ago, authorities have cracked down on human smuggling by sea, even by train. Their preferred mode of transportation now: trucks. Some migrants say they paid $7,000 each for a truck ride to the U.S. border. Though the price they end up paying the gangs is far higher.

"Through all sorts of activities that we really don't like - indentured servitude, prostitution," Papademetriou said.

Mexico authorities say they've intercepted almost 800 migrants entering the country illegally just this month. Border observers say that means many times that number made it through.