"Smuggling cases often hinge on migrants' stories"

That's the title of this interesting article in today's San Antonio Express-News. Here's how it begins:

They break the law when they cross the border illegally, but some undocumented immigrants making seasonal treks through South Texas are released to relatives already here and given papers they need to get what they came for in the first place — a job.

In exchange, the immigrants inform on the people who help them cross the border. When the smugglers are put on trial, their human cargo becomes the prosecutor's best friend.

There's also a surpisingly candid admission about how agents go about selecting which aliens to detain as material witnesses:

Choosing the material witnesses requires determining who will be a better witness, who saw or knows the most and who is more cooperative, said Jerry Robinette, acting special agent in charge of the San Antonio field office of U.S. Immigration and Customs Enforcement, an arm of the Department of Homeland Security.