(Photo : Reuters)

U.S authorities announced the discovery of the longest smuggling tunnel ever found on the Southwest border this weekend. The tunnel stretches more than three-quarters of a mile from an industrial site in Tijuana, Mexico to an area in San Diego.

It is assumed that the tunnel is designed to transport shipments like drugs due to features such as an extensive rail cart system, forced air ventilation, an elevator, high voltage electrical cables and panels, and a drainage system. 

The length of the tunnel is estimated to be more than 14 football fields. The discovery has stunned authorities. Meanwhile, there were no arrests made and no drugs were found in the area. On the other hand, U.S. authorities have not yet confirmed if the tunnel has exit points in the United States.

Lance LeNoir said: "This one blows past, the second-longest, we never really thought they had the moxie to go that far. They continue to surprise me."

The tunnel is a manifestation that there is a need for the Border Patrol officers and Homeland Security Investigations to look for more tunnels that could be used to smuggle drugs, humans, or facilitate any other illegal activities by cartels. The tunnel found was 70 feet underground and stretches several thousand feet. It is considered highly effective with its small and crudely built tunnels. 

This is the second tunnel found since August last year. Mexican law enforcement has identified its entrance and U.S. investigators are still mapping out the tunnel to determine if the exit points in the U.S. territory. The tunnel is estimated to extend a total of 4,309 feet. The second-longest tunnel was found in San Diego in 2014 and it was 2,966 feet long.

Officials said that the newly discovered tunnel is about 5.5 feet and 2 feet wide with an average depth of 70 feet below. There were also sandbags found in the tunnel that was suspected by the agents that were used to block the former exit points of the tunnel. Typically, sophisticated tunnels like this went under several warehouses in Otay Mesa and extended to open fields.

U.S. authorities believe that based on its trajectory, the tunnel once exited in San Diego. LeNoir's team, known as "tunnel rats" is a multi-agency task force specialized in investigating tunnels. LeNoir said that he tried to make his way through the tunnel, but said that he couldn't go very far due to blockage.

Authorities speculate that the incomplete offshoot of the tunnel had plugged an initial exit point and the cartels are building another. Jeff Stephenson, the spokesman of the Border Patrol, said: "The suspected previous exit became unsustainable for whatever reason, so they built a spur," Moreover, under U.S. federal law tunnels found within the territory of U.S. must be filled by concrete.

Cardell T. Morant, U.S. Immigration and Customs Enforcement's Homeland Security Investigations unit in San Diego acting special agent in charge, said: "The sophistication and length of this particular tunnel demonstrate the time-consuming efforts transnational criminal organizations will undertake to facilitate cross-border smuggling." 

Since 2006, authorities found 15 sophisticated tunnels in the borders of Califonia and Mexico that have lighting, ventilation, railway tracks, and hydraulic lifts.