In late October 2020, Border Patrol agents discovered a hand-dug tunnel under the border fence on West International Street in Nogales, approximately a half-mile west of the DeConcini Port of Entry.
The narrow passageway stretched just 10 feet, with an entry point in Mexico and a two-foot-by-two-foot exit about a yard north of the fence. It was likely being used, or was intended to be used, to move illegal drugs into the United States.
In a statement about the discovery, the Border Patrol said it was the 127th tunnel it had identified in its Tucson Sector since 1990. The majority of those were found in Nogales, where in some years, authorities on the U.S. and Mexican sides of of the fence uncovered as many as 20 tunnels in varying states of construction.
The abundance of subterranean drug-smuggling earned the city a dubious nickname: The Tunnel Capital of the United States.
But no more – at least for now. The tunnel busted on West International Street more than two years ago was the last one found in the city, a fact confirmed last week by U.S. Customs and Border Protection.
“You are correct. The last tunnel was October 2020,” a CBP spokesman wrote in an email.
So why has the tunneling – or at least the discovery of tunneling – stopped?
“That is due to the close coordination with the government of Mexico,” the CBP spokesman said. “They have bilateral patrol and information sharing on a real-time basis.”
Others cite changes in drug-smuggling economics, overall activity at the border, and an array of new laws enacted by U.S. states to legalize the product most associated with the tunnels: marijuana.
A matter of convenience
Nogales has several features that made it inviting for drug-tunneling.
First, the downtowns of Nogales, Ariz. and Nogales, Sonora meet at the border fence, offering more opportunities to build relatively short house-to-house tunnels, or to go unnoticed while parking a delivery vehicle above or next to an opening on a city street.
“It was almost a matter of convenience,” said Victor Manjarrez, professor at the Center for Law and Behavior at the University of Texas-El Paso, and the former patrol agent in charge of the Border Patrol’s Tucson and El Paso sectors. “If you can bring product into Nogales, Ariz., you were that much closer to I-19.”
If the drugs could make it past or around the I-19 checkpoint north of Tubac, the highway soon connects to Interstate 10, which in turn connects to other major highways from coast to coast, Manjarrez noted.
But Nogales has another feature that sets it apart from many other border cities: The local topography and related drainage infrastructure.
“It’s just the nature of Nogales, Sonora being at a higher elevation than Nogales, Ariz.,” said Santa Cruz County Sheriff David Hathaway. “Water flows downhill, sewage flows downhill. There’s always been tunnels under the street. It was just kind of a natural opportunity for smugglers to make use of that. Or to pop into the tunnel system briefly, go through a manhole cover, storm drain, and then pop back out.”
In addition to the drainage tunnels, smugglers have also made use of the International Outfall Interceptor, a cross-border sewer line, as a conduit for moving drugs into the United States. That’s led to several blockages, including a notorious incident in July 2015 when drug bundles clogged the pipeline under Morley Avenue, sending raw sewage pouring through the tunnel that smugglers had dug to the pipeline and out into the house from where it was constructed.
Hathaway noted that the legitimate drainage system under Ambos Nogales also provided physical support for new, illicit passageways.
“A lot of the things that were tunnels weren’t actually completely stand-alone tunnels,” he said. “They were trying to find a hard surface for an existing tunnel and they would use that as part of the shoring. They would build along the side of an existing underground concrete structure.”
In general, Manjarrez noted, Nogales’ drug tunnels were relatively unsophisticated. They paled in comparison to the million-dollar tunnel built by Joaquin “El Chapo” Guzman’s drug-smuggling organization that was discovered in 1990 in Douglas, Ariz., complete with hydraulic lifts and concrete reinforcement. Or the 4,309-foot-long structure busted 30 years later east of San Diego that included elevators, air ventilation and a rail system for moving loads under the border.
The longest tunnel on record in Nogales measured 481 feet, stretching from a home on E. Summit Place to a residence in the Buenos Aires neighborhood of Nogales, Sonora. It was discovered in early 2014. And when authorities have used the term “sophisticated” to describe local tunnels, it’s usually because they included basic electricity, water pumps and ventilation.
But in many cases, the constructions are more like Nogales’ last known drug tunnel, the one found on West International Street in October 2020. CBP described it at the time as a “rudimentary, hand-dug tunnel” that “had no shoring, ventilation or lighting.”
Cat and mouse
When CBP provides tallies of tunnel busts, it often refers to totals discovered since 1990 – the year of the infamous tunnel discovery in Douglas. In Nogales, some of the biggest years for tunnels came two decades later.
According to statistics previously provided by the Border Patrol, authorities in Ambos Nogales decommissioned 20 tunnels in 2010 alone, with some of the illicit activity happening right beneath the feet of law enforcement. In one case from August 2010, authorities discovered a clandestine passageway beneath the Dennis DeConcini Port of Entry after it created a sinkhole-like effect, causing a cross-border passenger bus to break through the pavement.
Manjarrez, who served as the Border Patrol’s Tucson Sector chief in 2010, said the tunnels were a high priority for the agency in Nogales.
“The agents took it on as a challenge. It was like, ‘OK, this is kind of a cat-and-mouse game. But we’re going to be better than you at this,’” he said. “That’s why I think you saw a lot of the innovation at the Nogales Station. A lot of it was just with agents. I think that was kind of neat.”
Announcements of busts began to include references to the Nogales Tunnel Team, whose members employed some of the same tools they had confiscated from tunnelers. Agents started using robots with names like the Inuktun 150 Pipe Inspection Crawler to probe the narrow and filthy drainages under the city for holes cut into the pipe by drug-smugglers. To thwart package deliveries through short-length shafts from one side of the fence to the other, CBP eliminated parking spaces next to the border on International Street. Surveillance increased as well.
Politicians also got into the act. A law passed in 2006 made building or financing an illegal cross-border tunnel a federal crime, punishable by up to 20 years in prison. The Border Tunnel Prevention Act of 2012 strengthened the law, making the use, construction or financing of a border tunnel a conspiracy offense, and specifying border tunneling as a wiretap-eligible crime.
How much any of it served to deter border-tunneling is hard to say.
Built for weed
The tunnels were about moving drugs from Mexico into the United States, not migrants, Manjarrez said. After all, the more people who pass through a tunnel, the more people who know it exists. And once they get through, “they’re free to talk.”
The drug that smugglers primarily moved through the Nogales tunnels was marijuana. That’s because drug-trafficking organizations needed to move large quantities of pot in order to make big profits, and the bulkiness and pungent odor of the loads made them difficult to sneak past port officers in commercial trucks or passenger vehicles.
“I remember most of the packages that came through tunnels, it was almost entirely marijuana. And it was uniquely shaped to fit through the tunnel passages, and sometimes through manhole covers,” said Sheriff Hathaway, who headed the local DEA office from 2009 to 2012.
On Dec. 13, 2010, federal investigators were tracking a suspicious van in Nogales when they saw a cylindrical bundle fall out of the vehicle. After a pursuit, they stopped the van and found more cylindrical packages containing a total of 2,194 pounds of marijuana.
In a news release issued at the time, U.S. Immigration and Customs Enforcement said the packages looked a lot like those seized during previous operations in which smugglers had ferried the drugs across the border from Mexico through tunnels. The van also had a trap door cut in its floor, suggesting the drugs had come from a subterranean entry point.
Those clues led law enforcement to a 10-inch diameter hole cut through the street surface just east of the Morley Avenue pedestrian crossing. The hole was covered with a piece of plywood and led to a 13-foot-long tunnel that began next to the border wall on the Mexican side of the barrier.
New laws, new drugs
Tunnel discoveries began to tail off later in the decade in Nogales. By 2020, there were only two: One in February and the other on Oct. 18 – the last one to be reported in the city.
So what happened to all the tunneling?
Hathaway cited a change in the types of drugs that are being smuggled into the United States.
“It seems like the main shift is that it’s gone away from marijuana now that marijuana is mostly legal in the U.S. for recreational and medicinal purposes,” he said.
“Now, it’s hard drugs coming through the port of entry. More potency in a small package,” he said. “I think the tunnel usage was primarily to get the bigger amounts through the border in a more clandestine manner.”
Federal data shows a sharp decline in marijuana seizures in the Border Patrol’s Tucson Sector that coincides with the decline in drug tunnel discoveries in Nogales. In Fiscal Year 2012, agents working in the sector seized nearly 1.2 million pounds of pot. That figure has decreased every year since then, to only 1,200 pounds in Fiscal Year 2022.
Meanwhile, seizures of fentanyl, a synthetic opioid that comes primarily in the form of a small pill, have skyrocketed at Nogales ports of entry. In a tweet earlier this week, Michael Humphries, CBP’s port director in Nogales, said his officers had already seized more fentanyl during the first three months of this fiscal year than in all of FY 2022 – which itself was a record-setting year.
Is it possible that smugglers are still moving drugs into Nogales through tunnels, but have gotten better at avoiding detection?
Reflecting on his days as an a DEA agent, Hathaway said he didn’t think so. Back then, he said, a lot of the tunnel busts were made with the help of informants.
“So many of those were from a network of informants – that’s how we detected them, we didn’t just randomly notice somebody popping up out of a tunnel,” he said. “Those informants are still there, but they’re not putting the finger on people using tunnels. So I would think it probably is just a paradigm shift, just a tactical shift toward other routes that are more cost effective.”
Considering Nogales’ favorable geography and subterranean infrastructure, does he think smugglers might resume their tunnel-digging in the future?
“I think that if it’s cost effective for some reason, they would probably exploit it again. I think it’s probably just the economics of the situation,” Hathaway said.
Manjarrez, the Border Patrol leader turned college professor, acknowledged the recent scarcity of drug tunnel busts. But, in terms of tunneling activity, he said, “It’s not zilch.”
“I really believe that it isn’t zilch; we just haven’t discovered those yet,” he said. “But I really don’t think the frequency is that great because there’s really not a requirement for that at this point.”
Manjarrez said he thinks the increase in the number of asylum-seekers arriving at the border in recent years has also impacted the Border Patrol’s drug interdiction efforts – as well as the drug-smugglers’ tactics – by tying up Border Patrol agents and CBP officers.
There’s been a significant decrease in the number of agents deployed in the field, Manjarrez said, because “they’re dealing with the high level of migration.”
“Now, if you’re a drug-trafficking organization and you don’t see the enforcement posture the same, why would you invest in a tunnel? Not only is it an investment of money, but in time,” he said.
“It all ebbs and flows. The migration levels at some point will start to come back down due to changes in policy and things of that nature. What you’re going to see is a spike in drug seizures, and you’ll see a spike in the discovery of tunnels,” Manjarrez said.
So could Nogales once again become the drug tunnel capital?
“Be careful where you drill,” he said.