Over the past several months, SEDENA (Secretary of of National Defense) of Mexico reported the dismantling and seizure of dozens of “narco-tunnels” between the U.S. and Mexico including six in Tijuana with a few of them identified as “Chapo-style” construction.

The tunnels come in varying degrees of sophistication and up to 6 football fields long in length with some completely walled off including electric rail transport systems, air conditioning, hidden access and all engineered to move large quantities of drugs across the U.S. southern border with Mexico in the state of Baja California.

One of the tunnels discovered that has been described as the “‘Chapo’ Guzmán style” was located in an alleged abandoned farm on Sor Juana Inés de la Cruz street, in the Nueva Tijuana neighborhood, according to sources in the Mexican press. Another was built on another farm, less than 50 meters from the first.

The discovery was made after local police were tipped off regarding armed individuals outside of the property and were believed to have been guarding the tunnels as well as the contraband being moved.

The governments of Mexico and the United States are cooperating in the follow-up investigation to trace the tunnel routes as well as identify any clues that could reveal exactly who was involved in the tunnel’s financing, construction and operation.

Besides illegal drugs, it is believed that the tunnels could have been used for human trafficking as well as moving weapons and undocumented migration.

So far, six people believed to have been involved with the tunnel’s operation have been arrested on charges of drug trafficking and are awaiting formal charges.