'Y'all ain't never been to Mexico.' How a road trip over the border took a deadly turn

Four South Carolinians in a white minivan pulled out the parking lot of a Motel 6 surrounded by palmettos and onto an expressway in Brownsville, Texas -- zooming past strip malls lined with taquerias, auto repair shops and law offices with Spanish names -- for the short drive to the Mexican border city of Matamoros.