The Deconcini Port Of Entry at Nogales, Arizona is one of the border's busiest places. And some of the activity is happening underground. Beneath the port, smugglers are digging their own tunnels linking the U.S. and Mexico, using drainage tunnels between the neighboring cities of Nogales Arizona and Nogales, Sonora as a starting point.

Smugglers are creating networks of smaller tunnels to transport drugs and humans between the two countries. The tunnels terminate in places like houses, abandoned buildings and busy parking lots.

Even as the use of such tunnels has increased – from 4 in 2006 to 18 in 2009 - so has the U.S. Border Patrol’s response. They have their own tunnel patrol team that spends hours crawling through the drainage tunnels, looking for illicit passageways. Occasionally, they come face to face with smugglers.

Agent Michael Scioli took Mark Duggan into the tunnels beneath Nogales in 2009. Scioli is part of the agency’s team of “tunnel rats.” He also talked to team commander Tom Pittman about enforcing the law in a dangerous, subterranean environment.

This smuggling tunnel featured a ventilation system to pump in fresh air.
A hand-dug smuggling tunnel underneath Nogales, complete with ceiling reinforcement beams.