Investigators can often establish how close a person is to the printer by how much that person paid for the bills. The printer may sell the bills for 10 cents on the dollar, while the person who actually uses the bill to buy something may have paid 50 cents on the dollar.
The driver, as it turns out, was a minor character in a network of 25 people, including the printer, middlemen, and passers of the fake currency. Secret Service agents traced the network back to the mastermind, who was arrested while printing the counterfeits.
"We always want to take the plant down and kill it," Hunter said. "That is the head of the snake. But usually we end up grabbing the tail first."
Since there is more U.S. currency circulated abroad than inside the United States, it comes as no surprise that much of the counterfeit business is also located abroad.
"This has grown into an international crime that has no boundaries," said Anthony M. Chapa, the special agent in charge in Los Angeles. "The tentacles are around the world. The same [people] who produce counterfeits that show up in Los Angeles produce the counterfeits that are being passed in Madrid, Spain, or Quito, Ecuador."
Since the international trade in counterfeits is closely linked to the drug and arms trades, it comes as no surprise that the number one foreign source of counterfeits in Los Angeles is Colombia.
The Colombian counterfeits are usually produced by offset printers.
"If it's done via inkjet technology, off the desktop computer, it's basically domestic," Hunter said. "If we get offset notes, from traditional printing methods, it's likely coming from overseas."
Several Latin American countries have adopted the U.S. currency as their own, something that agents warn could make their work even trickier.
"It's a whole new market for counterfeit money," Chapa said.
Already the U.S. currency is considered world tender.
"When Saddam Hussein emerged out of a hole in Iraq, you didn't see Mexican pesos coming out in suitcases, you saw $100 federal reserve notes," Hunter said.
One major concern of the U.S. Secret Service is that some financially corrupt governments may produce U.S. currency notes to prop up their economy.
In smaller operations notes are often passed to the public one by one. Passers usually look for dimly lit or busy environments.
"If you go to McDonald's at 12:15 in the said afternoon, you'll have a line out the door," Hunter. "The cashier won't pay that much attention to the money. It's a quick exchange."
Secret Service agents spend a considerable amount of time educating merchants on how to make sure currency is real.
"Counterfeit currency is a real problem for the mom-and-pop store," Stafford said. "If they accept a fake $100 bill, they can't exchange it for a real one."
To combat counterfeiting, the U.S. government regularly issues new bills with increasingly sophisticated security features. The paper that the money is printed on is not created from a wood product but made of cotton fiber.
The most recent bills contain new security threads and other features specifically designed to prevent color copying.
That, however, hasn't deterred counterfeiters. Two and a half weeks after the new $50 note was introduced, Hunter came across his first fake fifties.
"They weren't good reproductions," he said. "But they were good enough to pass at a local Texaco station."
Next week look for a National Geographic News report on how the Secret Service protects U.S. presidential candidates. Inside the U.S. Secret Service will be repeated on the National Geographic Channel on October 30. Check the TV schedule for details.
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