MANILA, Philippines -- The National Bureau of Investigation warned Tuesday the public, particularly frequent travelers, against purchasing airline tickets from unauthorized agents who could be part of or in connivance with unscrupulous groups involved in credit card fraud.

At the same time, the bureau also advised the public to be cautious in using their credit cards, saying these can be used in unauthorized purchases.

The warning came following the arrest of four Nigerians who were part of a syndicate which allegedly purchased electronic plane tickets through fraudulently acquired credit cards.

The suspects, who were arrested in Cavite over the weekend, were identified as Benson Alochukwa Onwuama, alias Uchenna Ekeyi, 27, the alleged leader of the group; Rotini Mumuni Oladapo, 36; Robinson Adatire, 52; Olarewaju Mojeed Ayegbusi, 24; all residing at Cecilio Apartments, Bacoor, Cavite.

Authorities are now on the hunt for the fifth suspect, Alochukwu Bartholomew Onwualu, 26, who remains at large.

The suspects, who were detained at the NBI jail, were charged for violation of Republic Act 8484 (Access Device Regulation Act of 1998), said Vicente de Guzman III, head of the NBI Anti-Fraud and Computer Crimes Division.

Seized from them were laptop computers, USB drives, router, Smart broadband antennas, invoices of money remittances, a skimming device, various blank credit cards and other materials they used in their illegal activities.

Palmer Mallari, executive office of NBI Anti-Fraud and Computer Crimes Division, explained that the suspects either used a skimming device to duplicate credit cards of unwitting victims, or hack information of legitimate credit card users from merchant websites.

“There are skimming devices that are very small, credit cardholders would not even notice that their cards were already swiped and copied using these devices,” Mallari said. “So it pays to personally bring your credit card to the cashier or keep an eye on your cards every time you make purchases.”

The Nigerians’ modus operandi involved offering, through the Internet, cheap airline tickets, domestic or international, to various destinations or discounted air fares.

Prospective victims pay in cash but the suspects buy the plane tickets under the buyer’s name using cloned, hacked or stolen credit card credentials online and pocket the cash they receive, the NBI said.

The NBI said the arrest of the suspects came following the complaint of Philippine Airlines.