How the U.S. Customs Service Works

U.S. Customs and Border Protection, which describes itself as "the primary enforcement agency protecting the nation's borders," has extensive air, land and marine resources -- including such state-of-the-art equipment as unmanned aerial vehicles -- for enforcing laws, as well as its own intelligence branch. Plus, it has an extensive canine corps for sniffing out drugs and other illegal substances [source: U.S. Customs and Border Protection].

Special agents deal with major criminal activities, including money laundering, drug smuggling, child pornography and what are known as exodus cases. Exodus cases involve the export of arms, weapons systems and other technology that can be used militarily against the U.S., according to customs agent Mann.

Another major area of investigation is commercial fraud. For example, in the Carolinas, special agents investigated people who brought in textiles illegally from other parts of world in attempts to beat the U.S. visa quota system, Mann says. As an illustration, let's say that a foreign manufacturer of textiles in Asia has a bilateral textile agreement with China and the United States. This bilateral agreement is part of a quota visa program, which says textiles imported into the United States must have a visa against that quota.

"Unfortunately, there are unscrupulous importers who purchase textiles from China, ship them to a third country and try to import them into the United States as products of that third country," Mann says. "This undermines the visa quota program and brings goods in that compete directly with our own textile capabilities. Millions and millions of dollars can be at stake here."

Similarly, commercial fraud is being conducted around the import of plain white T-shirts. (These are a hot commodity -- statistics say that the average American consumes 15 T-shirts a year from sporting events, concerts and work.) If T-shirt printers can get cheaper shirts brought in and evade duty rates, they can be more competitive.