For millions of travelers who visit foreign countries, it's not just their passports, but their fingerprints, that they need to hand over at the border.
Because fingerprints are unique to each individual, fingerprint scanning at airports and other ports of entry helps security officials quickly identify criminals, terrorists, immigration violators and others. While not foolproof, for some countries, the system is the first line of defense against enemies of the state and other unwanted visitors.
But, earlier this month, Japanese officials arrested a Chinese woman who took a particularly extreme measure to evade detection. She paid a plastic surgeon to surgically alter her fingerprints.
Lin Rong, 27, was originally arrested Dec. 5 for faking a marriage license after she'd already entered the country, Japanese officials said. That' s when police saw scars on her hands and realized that she might have been guilty of more.
"During the course of the investigation, police found that she passed through the checkpoint using fake fingerprints," said Nobuyuki Kawai, director of the International Crime Office of Japan's National Police Agency.
He said Rong had previously been deported but sneaked back into the country to work in a restaurant or a bar.
Although local reports said she paid about $15,000 for the fingerprint transplant surgery, Kawai said Rong told officers she paid roughly $1,500 for the procedure that swapped fingerprints from her right and left hands.
Patches of skin from her thumbs and index fingers were reportedly removed and then grafted on to the ends of fingers on the opposite hand. As a result, Rong's identity was not detected when she re-entered Japan illegally.
Since Japan started checking the fingerprints of foreign visitors in 2007, Kawai said, immigration officials have caught eight other people who tried to alter their fingerprints through various techniques.
But, he said, this was the first time officials had identified an illegal immigrant who used surgery to fake fingerprints.
"This is the first case," Kawai said. "But please keep in mind that we don't know if there are any other cases. You never know unless you catch the person."
Rong, who is still in custody, could either serve time in a prison or be immediately deported, he said. And Kawai added that the immigration department is tightening security at airport checkpoints.
"We are sure they are trying to be more careful at border control," he said. "So we hope we can prevent similar cases in the future."
But should this example raise a warning flag for the United States and other countries that use fingerprint scanning and other biometric security systems?
Although Rong's method of deception was especially drastic, she was not the first to figure out how to fool a fingerprint scanner.
In January of this year, it was reported that a South Korean woman blocked from entering Japan apparently slipped past the screening system by placing special tape over her fingerprints.
The silicon covering foiled the scanning device and didn't alert officials that she had been deported in 2007 for overstaying and was barred from re-entry for five years. Immigration officials later found her inside the country.