On June 7, Luis Barrera arrived at Miami International Airport aboard a flight from Caracas. He was arrested soon after presenting to Customs and Border Protection officers a Venezuelan passport containing a U.S. visa obtained at a U.S. consulate in Venezuela.

Barrera was charged with visa fraud, not because his visa was fake — but because he had used it again after illegally overstaying his allotted time twice before.

Barrera was only one in a long string of foreign nationals arrested at MIA and other airports around the country on visa charges in the last year.

One common denominator in many of these cases is that the defendants have previously overstayed their visas, entered the United States illegally or been deported.

Another commonality is that the travelers have been discovered by CBP officers on arrival in the United States, not by State Department consuls when they apply for visas abroad.

While it would seem consuls are issuing visas to foreign nationals who are not entitled to them, U.S. officials say the consuls are doing their job properly.

Consuls generally issue five- and 10-year visas to foreign travelers who apply for them. But these visas are not a guarantee that the travelers will be automatically admitted into the United States. That decision rests with CBP passport control officers who generally grant six-month stays to travelers with the long-term visas issued by consuls. If the traveler leaves the United States before the authorized time expires, then he can use the long-term visa again. If there is an overstay, he could be denied entry or arrested if fraud is detected.

A State Department official explained that foreign nationals with genuine visas who are denied entry because of prior transgressions generally carry visas good for five or 10 years.

These visas are issued for multiple entries into the United States with the understanding that visitors must leave the country at the end of their authorized time. If they overstay, the visa becomes invalid when they try to return.

On arrival, CBP generally gives a foreign visitor six months to stay in the United States. But if these visitors overstay their allotted time, consuls would only become aware of the violation when the foreign national tries to renew the long-term visa, the official said.

Thus, CBP officers are the ones who discover the violations when the foreign visitors attempt to return to the United States using the same long-term visa.

Fraud cases in Miami federal court do not indicate whether the foreign visitors arrested carried long-term visas.

But in the case of Barrera, who was arrested June 7, a CBP investigator said the defendant added false entry stamps to his passport showing he had returned to Venezuela from the United States before his visa time expired.

By examining these stamps closely, CBP investigators concluded Barrera had overstayed twice — once in 2007 and again in 2009.

“During secondary interview, the defendant admitted that he had overstayed two entries and obtained the backdated stamps to conceal his overstays in the United States,” the CBP investigator said in an affidavit.

Barrera’s attorney could not be reached for comment.

Other cases, however, clearly leave the impression that foreign visitors obtained their visas by lying to a consul who did not immediately discover a prior overstay.