Border security

Tight squeeze: Economics make border drug tunnels narrower

In  just a single month this spring, U.S. immigration officials uncovered three cross-border drug tunnels, the latest of more than 75 cross-border tunnels discovered in the last five years.

What's different about the recent tunnels is that most are significantly smaller and don't boast the technological advances that officials saw a few years ago.

William Sherman, special agent in charge for the U.S. Drug Enforcement Administration in San Diego, said drug cartels have moved toward tunnels that require a smaller investment because of the high risk of being discovered.

"It saves them money.... In at least the previous six tunnels, we've hit those before they got any narcotics through. So it was a tremendous amount of money and resources that they wasted when we took those off," Sherman said. "I think [they're thinking], ‘Hey, they're finding these pretty quick, we maybe shouldn't put as much money into them, even if it takes us more time to get the loads through.'"