There are at least 180 cross-border tunnels and intricate drainage systems between Mexico and California and Arizona, according to the Border Patrol, and drug dealers and human traffickers, known as coyotes, use these tunnels to move drugs and illegally smuggle people across the border largely undetected. As the number of tunnels grow and become more sophisticated, Border Patrol agents say they are falling behind in finding technology that will detect them. MEXICO'S UNFILLED BORDER TUNNELS A SECURITY RISK, US OFFICIALS SAYLance Lenoir, a member of the Border Patrol elite tunnel team working out of the San Diego Sector, said his team of five agents patrol the daunting miles of storm drains that lead them to connecting tunnels along the border. But not only is it ineffective in many areas along the border, it is not available to enough agents to make a major impact. The noise from nearby traffic and major freeways and unregulated radio traffic from Mexico impairs an agent’s ability to detect what’s happening below ground.

Source: Fox News July 05, 2017 18:11 UTC