The 500 meters-long tunnel was dug 18.5 meters deep and had reinforced walls and rail tracks. It had electricity and ventilation systems installed in it as well.
Authorities found the tunnel on information provided by Homeland Security agents who, in the late hours last Friday, were conducting surveillance on a residence and a known drug trafficking warehouse. The San Diego warehouse is situated only 300 meters north of the border.
Prior surveillance identified multiple vehicles that commuted to and from the locations in question, according to court documents.
The first suspect drove from the residence to the warehouse on May 12, where she was quickly waved. Two hours later, she drove away and returned to the residence. Police noted that, given her visual behavior and proximity to the border, there was a reasonable chance that she was involved in drug trafficking activity.
Half an hour after the first suspect entered the house, another vehicle arrived but stayed for less than 10 minutes. Police conducted a traffic stop on the second suspect and a subsequent search of the vehicle turned up 240 kilogram-sized bricks of cocaine.
Fifteen minutes after the traffic stop, a third vehicle, with two suspects inside, arrived at the residence. Investigators noted that they stayed for only two minutes but kept the trunk open the entire time.
The vehicle was stopped at a nearby market, where police discovered 55 bricks of cocaine in the trunk.
With two large-scale seizures made in quick succession of one another, U.S. authorities conducted a raid on the warehouse, which led to the discovery of the tunnel, the entrance of which was carved through the cement floor.
A total of six individuals were taken into custody, including the three arrested from the two traffic stops. Additionally, the operation saw 1,762 pounds of cocaine seized by police, along with 164 pounds of methamphetamine.
“There is no more light at the end of this narco-tunnel,” said U.S. Attorney Randy Grossman following the raid. “We will take down every subterranean smuggling route we find to keep illicit drugs from reaching our streets and destroying our families and communities.”
Since 1993, a total of 90 subterranean passages connecting Mexico and the state of California have been uncovered. Of those, 27 are said to have been constructed with the same level of sophistication as the one under Otay Mesa, according to the DOJ.
