OTAY MESA, Calif. — The end of the tunnel emerges a half mile from the border with Mexico in a room at a nondescript warehouse that is identified on a sign outside as “V & F Distribution Ltd.”
The Immigration and Customs Enforcement officer opens a padlocked hatch and lifts it to reveal an eight-foot shaft that leads down to the longest underground smuggling passageway discovered by law enforcement so far.
Above ground, it’s a bright, southern California day. An empty lot stands between the warehouse and the border, which is blocked by a double fence. Binoculars are needed to see the warehouse on the Mexican side where the drug traffickers began their work almost two years ago in this busy corridor, which handles most of the truck crossings in Southern California.
Border Patrol agents kept a watchful eye on the fence here for months as smugglers beneath their feet moved an unknown quantity of contraband into the United States.
To dig a half-mile long tunnel is not a simple task. Those who engineered the project had to install lights along with a ventilation and drainage system. An 83-foot concrete shaft reinforced with concrete blocks was sunk on the Mexican side. The smugglers also had to lease the warehouse on the U.S. side without the owner knowing its purpose. ICE estimates that it would cost a U.S. construction company $2 million to build a similar tunnel, although the agent said it is doubtful the smugglers had to invest that much. Whatever the cost, the money invested could easily be recouped in one night. And the tunnel was believed to be in operation for 18 months.
The ICE agent steps down the ladder holding a flashlight and shines it down the passageway. A spur about half way to the warehouse shot off to the side, but was abandoned by the diggers. ICE believes they were attempting to reach another building, but abandoned that plan, possibly after securing the V & F location.
About 100 feet down the passageway, groundwater blocks progress. Once the tunnel was discovered and the drainage system no longer maintained, the tunnel began to fill in. A few feet from the border, ICE also sunk a hole and filled it with concrete to render it temporarily inoperable. The agency is seeking additional funds to completely shut it down.
Human intelligence on the Mexican side of the border tipped ICE agents off that there was a tunnel somewhere in the vicinity. One arrest has been made so far in the case.
The ICE agent, who declined to be identified or have his face photographed in order maintain operation security, is a member of a joint tunnel detection task force that is made up of ICE, Border Patrol, Drug Enforcement Agency and California law enforcement officers.
After receiving the tip, the agents called Joint Task Force North based at Fort Bliss, Texas, to request help locating the tunnel.
A team dispatched to Otay Mesa used ground-penetrating radar that showed anomalies that indicated the possibility of a tunnel.
“We never believed it would reach a half mile from the border,” the ICE agent says.
The science of tunnel detection goes back until at least World War II, when both Germans and the allies tried to prevent prisoners of war from digging escape routes, according to Army Lt. Col. Steve Baker, chief of tunnel detection operations at JTF North.
The training and technology used to hunt tunnels along the Mexican and Canadian borders has immediate applications in Southwest Asia as ground forces there attempt to root out Taliban holdouts in caves in Afghanistan’s mountains, Baker said.
Until recently, several different organizations within the military have worked on tunnel/cave detection problems in a “stovepipe” manner, Baker added. And within the federal law enforcement communities, no single agency had taken the lead, either.
Lately, Northcom’s futures group has been given the task of leading tunnel technology development. JTF North has also sponsored two tunnel detection conferences.
“The technology … also helps us in the protection of U.S. assets throughout the world like embassies or other key facilities that people may be trying to tunnel into,” Baker said.
Universities and private companies, under JTF North auspices, have volunteered their time to help search for the tunnels. In doing so, they have a chance to test some cutting edge technologies.
Among the methods used are seismic techniques, which use pulses of sound to look for passageways. Satellite imagery can be used to spot excavated soil.
Resistivity involves pounding a series of stakes into the ground with sensors attached. Electrical signals are transmitted downwards, and reflect anomalies back to the stakes. “Obviously that’s hard to do that one if you’re working on asphalt pavement,” Baker said.
Gradiometry is a relatively new method that involves reading slight anomalies in electro-magnetic or gravitational fields to determine if there is a void underground.
After discovering the tunnel, JTF North invited vendors to a non-funded event where they demonstrated how well their new technologies worked in finding the tunnel. Northcom is currently evaluating those technologies.
After a tunnel is discovered, JTF North’s work is not done. Afterwards, engineers help shut the tunnels down.
“We figure out the most cost-effective, structurally sound ways to close these tunnels so they aren’t used again,” Baker said.