The U.S. official says the two men arrested in Amsterdam did not know each other and were not traveling together.
The official, speaking on condition of anonymity to discuss the ongoing investigation, says both men missed flights to Dulles International Airport from Chicago, and United Airlines then booked them on the same flight to Amsterdam. The men were sitting near each other on the flight.
Another U.S. official, who also spoke on condition of anonymity, says that when Customs officials discovered one passenger was not on the flight from Dulles to Dubai, they called the plane back to the gate and removed his luggage. It was then they discovered suspicious items in his bag.