SAN DIEGO -- A drug tunnel under construction was discovered Tuesday morning by Baja State Police in an unusual area of Tijuana.
The tunnel was found in a nondescript structure across the street from one of Baja's largest cemeteries, about a mile west of the San Ysidro border crossing.
Most of the tunnels that have been discovered have been further east in the Otay Mesa area, where the soil is softer, sandier and easier to plow through.
According to investigators, the usual suspects -- members of a Mexican drug cartel -- are involved.
Five people have been arrested in connection with the discovery.
Michael Lettieri of the Trans-Border Institute says while drug tunnels continue to be used primarily to smuggle marijuana into the U.S., it's actually an old strategy.
"Cartels are making most of their money, and what they're fighting over now, is increasing the heroin and meth into this country. Heroin and methamphetamines are really easy to smuggle in cars, in water bottles. It's small, it's compact and it has tremendous value once it gets across for a very small amount," said Lettieri.
Lettieri said cartels are likely to turn to other smuggling strategies such as catapults, submarines and drones to get drugs north of the border.