We Went Into a Narco-Tunnel With the Elite ‘Tunnel Rats’

SAN DIEGO—The steady rumble of semitrailer engines is broken only by the screeching and hissing of air brakes along the northbound lane approaching the Otay Mesa Port of Entry, as U.S. Border Patrol agents descend by ladder 18 feet into the narrow shaft of a narco-tunnel once used to smuggle drugs from Tijuana to San Diego.

The commotion on the surface fades to silence as a couple of agents guide two Epoch Times reporters down into the tomb-like darkness.

Michael Sablan, a Border Patrol agent for two decades and a member of the San Diego Tunnel Task Force, known as the “Tunnel Rats,” leads the way through the cramped underground passage—about three feet in height and less in width.

Wearing helmets with headlamps and knee pads, the team crawls on hands, elbows and knees over sharp rocks chipped away from the tunnel walls. The air is still and musty, with a lingering earthy odor mixed with clammy sweat.

The passage, dimly lit with bulbs strung together with extension cords, is equipped with plastic PVC pipes for ventilation and a shallow rail system.

“We’re located inside one of what we call sophisticated tunnels,” Gerardo Gutierrez, a U.S. Customs and Border Protection (CBP) spokesman, said from inside the tunnel, which slopes to about 20 feet in places.

But, despite the “sophistication,” the digging process—often done with nothing more than a pick and shovel, maybe a jackhammer—is rudimentary, he said.

A flatbed rail cart slightly longer than a mechanic’s creeper complete with cushions sits eerily on narrow tracks, about 18 inches apart.

“The rail carts are used to transport narcotics, and to haul dirt out of the tunnels when they’re being built,” Gutierrez told The Epoch Times.

Although this rail cart wasn’t motorized, others are equipped with electric golf cart motors to easily glide along the tunnel tracks in forward or reverse, Sablan said.

As one goes deeper into recesses of the tunnel, spray-painted graffiti along the walls tags it as the subterranean territory of the Sinaloa Cartel.

The cartel used the tunnel to smuggle narcotics from Tijuana to a warehouse in Otay Mesa, an industrial, commercial, and residential area in the southern exclave of San Diego along the U.S.–Mexico border. The underground route was used for about two years before it was discovered in 2013.

A former U.S. marine with a family history of service in military and law enforcement, Sablan is proud to be a member of the Tunnel Rats.

“One of the reasons why I got into this line of work, or specifically with drug tunnels, is because I think everybody in the United States can kind of relate to the effects of drug use, either losing a personal family member or a friend,” said Sablan. He’s been assigned to the tunnel team for the last four years.

“I have lost several—both friends and family—to drug use,” he said. “If I could make a difference, especially with narcotics coming north—the fentanyl surge and other various forms of narcotics—that, to me, is the greatest reward, and it’s worth the risk we take every day going inside these drug tunnels.”

Under the direction of CBP and its parent agency, the Department of Homeland Security, the Border Patrol Tunnel Rats work alongside Homeland Security Investigations, the Drug Enforcement Administration (DEA), and local sheriffs, he said.

“Our job is solely to target, find, locate, and remediate drug tunnels,” Sablan said.

Once a tunnel is uncovered and fully investigated, federal authorities coordinate the “remediation” process, which usually means pumping thousands of gallons of concrete down the shafts to permanently seal them.

 Human Smuggling Rare in Tunnels

The tunnels are rarely used for human smuggling, because cartels want to keep their narcotics operations and tunnel locations secret from illegal aliens. But, it did happen once, Sablan said.

Several months after the tunnel was discovered, but before it was filled with concrete, a human smuggler in Tijuana found the entrance and moved 28 Chinese nationals through it. But, an agent near the tunnel exit spotted them and they were arrested, he said.

“[Agents] backtracked where they came from, and they saw this hole in the ground,” Sablan said. “And, so this is basically where they exited.”

Lance LeNoir, a Border Patrol agent since 1998 who was on-site at the tunnel exit on Sept. 17, told The Epoch Times that “some tweakers” in Tijuana used it to smuggle the Chinese nationals under the border.

It was the only time there has been any evidence the tunnel was used for human smuggling, Lenoir said.

“That was more or less a consequence of our bureaucratic process and remediation,” he said.

As time passed, the cartels decided to reuse the tunnel entrance on the Mexican side.

“They went back in three years later, in 2016, and they dug another tunnel using the same entrance as the one from 2013, and they just dug alongside it,” Sablan said.

But through “source information and other means,” including working with Mexican counterparts, the tunnel team was able to intercept it.

“We were able to stop that one from actually becoming completed,” Sablan said.

About 1,800 feet of the original tunnel was sealed with concrete on the U.S. side, but the tunnel remained open south of the border because “Mexico does not remediate,” LeNoir said.

“They go back into the tunnel in Mexico, because why wouldn’t they? They already have half of it built, essentially,” he said. “So, they come up to where we poured concrete and either go around it or shadow it.”

When the second tunnel was found in 2016, LeNoir seized it for training.

“At that point, it’s like ‘I’m done with this. I’m not doing this. I’m taking it,’” he said. “I wanted to leave it in its pristine state because nowhere else in the United States do you have an actual tunnel in which you can train and test.

“I wanted something that was pure, no mock-up or simulation.”

The McGregor tunnel, named after a man who helped the Border Patrol disguise the tunnel shaft to look like a manhole cover to a sewer drain, was assessed by geophysicists who determined it was safe to use for training, LeNoir said.

The soft soil in Otay Mesa is ideal for cartel crews digging tunnels with hand tools and contains enough moisture to keep walls firm and less apt to collapse, Gutierrez said.

Both tunnels were built when old “landing mat” corrugated metal fencing was all that separated the United States from Mexico. That was before the new primary and secondary smart border walls—equipped with lighting, cameras, and sensors—were completed in the San Diego sector under the Trump administration.

The gap—about the length of three football fields—that remained open on Otay Mountain during the Biden-era border crisis is now sealed, Gutierrez said.

Creating the Task Force

LeNoir, an operations supervisor, helped create the San Diego Tunnel Task Force in 2010 and has led the team ever since.

The colloquial name “Tunnel Rats” pays homage to Vietnam War veterans who cleared Viet Cong tunnels, LeNoir said.

“It’s a direct tribute to the men and women who came before us, who actually did that in much harsher conditions than we could ever possibly imagine,” he said. “They were cool … and they’re heroes to us.”

As more tunnels were created along the southwest border region in California and Arizona, the Border Patrol realized the need for a specialized unit to deal exclusively with these threats, LeNoir said.

“That’s all I do. That’s all this team does,” he said.

Without specialized training and equipment for dealing with tunnels, “we started from scratch,” LeNoir said.

He quickly learned that “really nobody specialized in this line of work,” not even fire and rescue departments.

Working in confined spaces is one thing, he said, but heading into “hand-built drug tunnels for incredibly long distances,” requires first responder, rescue, and other training.

“We basically created our own playbook,” he said. “And, we’re still evolving.”

Timeline

Since 1993, nearly 200 tunnels have been discovered along the southwest U.S.–Mexico border, about half of them in the San Diego area, according to the Border Patrol.

Not surprisingly, in 2015, infamous drug lord Joaquin Guzmán Loera, better known as El Chapo, escaped from his maximum-security prison cell in Altiplano—near Mexico City—through an elaborate tunnel.

El Chapo’s Sinaloa cartel built the first cross-border “narcotúnel” in 1989. Guzmán is currently serving a life sentence at ADX Florence Supermax prison in Florence, Colorado.

Today, the drug trade in Tijuana is primarily controlled by the Sinaloa and Jalisco New Generation cartels with some remnants of the Tijuana Cartel once run by Arellano Félix and his brothers, according to the Border Patrol.

Mexican Tunnel Crews Murdered

Cartels go to extreme lengths to ensure their lucrative drug smuggling operations are kept secret from rivals and police. And because paranoia runs deep, they’re known to routinely murder their own tunnel crews to silence them when their work is finished or a tunnel location is compromised.

“We know through investigations and interviewing people, that’s what they do,” Gutierrez said. “Once they’re done, they usually get rid of them. That way, they don’t have any people talking.”

Intelligence sources have told the Border Patrol “these crews have been killed off so they don’t talk,” he said in a follow-up email to The Epoch Times.

In other cases, the cartels blindfold or put bags over the men’s heads and take them by van to the tunnels. They’re not allowed outside and see nothing except the inside of the tunnel, he said.

“The cartels have killed some of these tunnel crews … when a tunnel was busted before it could be completed,” Gutierrez said.

Gutierrez said the cartels lure people through forced labor.

Forced Labor

Sometimes the tunnel diggers are paid for their work with drugs, but there have been cases where they’ve been coerced to dig narco-tunnels under horrific conditions.

In 2013, El Universal, a Mexican daily newspaper, exposed a harrowing account of the Sinaloa Cartel abducting 17 men and enslaving them to dig a narco-tunnel.

It was later widely reported by several major American media outlets that the cartels recruited workers at industrial areas and bus stations in Tijuana, promising them good-paying construction jobs and passage to the United States.

Instead, when the men showed up for work at a warehouse, they were blindfolded, locked inside and forced at gunpoint to dig a 1,300-foot tunnel by hand for up to 14 hours a day. They were held captive for more than three months until rescued by federal authorities.

“We have heard about the horrible conditions,” Gutierrez said.

Longest Tunnel Ever Found

The Baja Metro Tunnel, as it’s known, running from Tijuana to San Diego, was discovered in August 2019, about a half-mile west of Otay Mesa Port of Entry. Spanning more than three quarters of a mile—4,068 feet from the border with a total length of 4,309 feet—it’s recognized by CBP as the longest illicit tunnel ever uncovered along the southwest border.

The tunnel was about five-and-a-half feet tall and two feet wide with an average depth of 70 feet from the surface, according to a 2020 CBP statement.

The tunnel team nearly caught cartel tunnelers in another tunnel in Otay Mesa.

“The Port of Entry was at the time doing some construction work, and one of the heavy vehicles collapsed the tunnel while they were working … and created a sinkhole,” LeNoir said.

“They didn’t know what to make of it. They saw some sandbags and called us. We knew what it was instantly because we’ve seen that before.”

As Border Patrol Tunnel Rats dug back into the trench about 15 to 20 feet down, LeNoir said they could hear the Mexican tunnelers drilling and digging on the other side.

“They were probably no more than 10 feet away from us, but it took us about another two hours to get there,” he said. “They were working the exact same hours as the construction crew up top to mask their activity. And, once it turned 5 o'clock, they took off.

“We weren’t able to tap into that till about 5:10, so we missed them by 10 minutes. In fact, we were so close, there was still cigarette smoke wafting in the tunnel itself. That was the closest we’ve ever gotten to catching [them].”

The Shift to Hard Drugs

As tunnels became more prevalent in the mid-to-late ’90s and early 2000s, they were almost exclusively built to smuggle marijuana, LeNoir said.

Until about 2015, it was the primary product going north, but by about 2017 as marijuana was decriminalized and legalized, cartels began moving harder drugs through tunnels, he said.

In August 2018, authorities found a 600-foot narco-tunnel—about 22 feet deep, 5 feet tall, and 3 feet wide—that ran from a trap door under a bed in a home in Mexico to the kitchen of an abandoned KFC restaurant in San Luis, Arizona, near Yuma. Smugglers used a rope system to haul narcotics up through a narrow opening at the former KFC site.

The arrest led authorities to the tunnel. Agents knew it was exclusively used to move hard narcotics because the “access portal” was only about the size of a football, LeNoir said.

Ivan Lopez, a Yuma resident who owned the building that once housed the KFC, was pulled over by a San Luis police officer during a routine traffic stop. Hidden in toolboxes inside his vehicle were 370 pounds of hard narcotics, including methamphetamine, cocaine, fentanyl.

The 7.5 kilos of fentanyl that were seized—a record at the time—contained enough fatal doses to kill 3.5 million people, or the entire population of San Diego County, according to CBP. 

“We started cluing in when we intercepted the Yuma tunnel,” LeNoir said. “We started realizing the paradigm was shifting.”

Because hard narcotics are less bulky than marijuana, they’re much easier for the cartels to smuggle, LeNoir said.

“It’s worth 100 times more and the effort is 100 times less. It made perfect sense,” he said. “We knew this was coming, and we were scared … We found out that it was cocaine, fentanyl, heroin, methamphetamine—the whole cocktail.”

With the deadly synthetic opioid fentanyl linked to hundreds of thousands of overdose deaths in the United States, the federal government has cracked down hard on fentanyl smugglers. The precursor chemicals and ingredients to make illicit fentanyl come mainly from China to Mexico, according to the DEA’s 2025 National Drug Threat Assessment report.

“We’re seeing less fentanyl,” LeNoir said. “Unfortunately, we’re seeing a lot more cocaine that’s come back in vogue.”

 Tunnel Detection

In the past, and as recently as 2025, Border Patrol has intercepted the tunnels by drilling into them and monitoring activity inside, Gutierrez said.

“We continued to monitor them and watch [cartel crews] leave and go back south into Mexico via the tunnel,” he said.

Tunnel teams use unmanned robotic prototypes to clear the tunnels of any potential booby traps set by cartels before they enter the tunnels.

No tunnel team members have ever been killed in the tunnels, nor have any bodies of the Mexican tunnelers been found in them, Gutierrez said.

While advances in ground-penetrating radar and geological tracking, including seismic, acoustic and microgravity sensors, have helped authorities detect narco-tunnels, the use of such technology is challenging, especially under urban industrial areas like Otay Mesa that are cluttered with complex electrical grids and gas and water lines.

Surveillance of warehouses and industrial areas near the border, and traditional police detective work using informants and tips remain the best methods.

“It’s not just underground utilities that cause issues but the geology itself, because of the metals that are naturally present, along with all the above-ground noise from high traffic areas that make detection difficult,” Gutierrez said.

CBP relies less on surveillance and more on public outreach, which really means “just talking to people that work in or around the business areas and developing good relationships with business owners and workers to report if they hear or see something unusual,” he said.

Information about any suspected criminal activity is passed on to local law enforcement, Gutierrez said.

Despite the increased use of drones, he said the cartels will continue digging tunnels and exploit every means possible to smuggle narcotics by land, air, and sea.