State police officers patrol a highway between Ciudad Victoria and Matamoros, in northeast Mexico, in 2011. Mexico's drug and turf wars have descended on the once tourist friendly border town of Matamoros. Alexandre Meneghini/AP hide caption

itoggle caption Alexandre Meneghini/AP

A Mexican guard at a prison in Tijuana where 17 men are being held on charges they were digging a drug-smuggling tunnel from Tijuana to the U.S. border at San Diego. The men say they were kidnapped and forced to do the work. Special to NPR hide caption

itoggle caption Special to NPR