Federal agents have discovered the longest drug-smuggling tunnel in San Diego Southwest border

Federal agents have found a drug smuggling tunnel that stretches about three-quarters of a mile -- the longest ever determined along the Southwest border.

The 4,309-foot tunnel starts in Tijuana, Mexico, pretty much 250 toes south of the border. It travels underground into San Diego County, California.

It is ready with air ventilation, electricity, an in depth rail and cart system, or even an elevator at the each entrance, according to US Customs and Border Protection.

"The sophistication of this tunnel demonstrates the willpower and financial sources of the cartels," Drug Enforcement Administration's Special Agent in Charge John W. Callery said in a announcement Wednesday.

"Although the cartels will continue to use their assets to try to breach our border, the DEA and our partners at the Tunnel Task Force will continue to apply our sources to make sure they fail, that our border is secure, and that tunnels like this are close right down to stem the go with the flow of deadly drugs getting into the United States."

The tunnel, located by means of CBP and its partners following a multiyear investigation, lays 70 toes below the ground and is ready five feet, 5 inches tall and two ft wide.

The discovery has not yet brought about any arrests or seizures. But agents will continue their investigation, in line with CBP Deputy Chief Patrol Agent Aaron Heitke.

"I am confident that our tough work and determination to uphold the law will lead to future arrests and seizures," Heitke said in a declaration.

The next longest tunnel became also located in San Diego in 2014 and changed into 3,259 feet long.

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