To match story WITNESS-IMMIGRATION/BORDER

 
To match story WITNESS-IMMIGRATION/BORDER
U.S. Border Patrol agents look at infrared surveillance video in a "scope truck" stationed at the U.S. Mexico border in Laredo, Texas in this early May 3, 2006 file photo. The camera gives the agents the ability to see the heat signature given off by humans hiding along the Rio Grande river. To match story WITNESS-IMMIGRATION/BORDER REUTERS/Rick Wilking/File (UNITED STATES)