Agents held three immigrants as witnesses and arrested two men accused of human smuggling.
An inspection at a U.S. Border Patrol checkpoint around 10:15 a.m. found the driver didn't have a commercial license and the passenger didn't have legal papers.
A second inspection revealed 30 illegal immigrants, including one child, inside a compartment hidden by furniture in the back of the truck, accessible by a trap door.
Border Patrol agent Mark Endicott declined to release the names of the suspected smugglers. He says the driver is a Mexican citizen who had a border-crossing card to legally enter the United States.