Uncertainly abounds over the fate of missing Malaysia Airlines Flight 370, that disappeared from radar suddenly on Saturday night, and passengers using stolen passports raises some serious questions about possible terrorism.

Two passengers listed on the flight reported their passports stolen. Could those stolen passports indicate a terrorist act?

Italian Luigi Maraldi and Austrian Christian Kozel have confirmed that they were not on the flight. Both also reported their passports stolen.

Malaysian authorities apparently did not check the stolen documents on an international law enforcement agency database, CNN has learned.

After the careful review of the passenger manifest, Austria has denied that Kozel was on the flight as the list had shown. The Austrian citizen was safe and sound, and his passport had been stolen two years ago, Austrian Foreign Ministry spokesman Martin Weiss said.

And the same of the Italian passenger on the list, Italy’s foreign ministry confirmed that no Italians were on the flight, even though an Italian was listed on the manifest.

On Saturday, Italian police visited the home of the parents of Luigi to inform them about the disappearance of his flight, said a police official in Cesena, in northern Italy.

But strangely, Maraldi’s father, Walter, told police that he had just spoken to his son, who had called them to let them know he was O.K. and was not on that flight. Luigi was vacationing in Thailand, his father said. The police official said that he had reported his passport stolen in Malaysia last August and that he had already replaced it.

When asked whether terrorism was suspected, Malaysian Prime Minister Najib Razak said, “We are looking at all possibilities, but it is too early to make any conclusive remarks.”

Law enforcement told CNN on Saturday that U.S. government agencies were informed and the names of the persons whose passports were stolen have been circulated and checked, but concludes that there is nothing at this point to indicate foul play.

The National Transportation Safety Board (NTSB) has sent a team of its investigators to Asia to help with the investigation, the agency said.

“They will be positioned to offer U.S. assistance,” the NTSB said of the team, which also includes technical advisers from Boeing and the Federal Aviation Administration.

U.S. authorities have not ruled out terrorism as the cause in the disappearance of Flight 370.

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