Hundred-foot long drug tunnel discovered across Mexico-US border The tunnel, the latest of 22 illicit passageways found in the Nogales area in the past three years, was likely completed this week. Agents made no arrests, but found 550 pounds of marijuana inside in bundles while securing the tunnel. In 2010, a tunnel was also found under the concrete channel of the Rio Grande River between El Paso, Texas, and Ciudad Juarez in Mexico.