Shady Passenger
This person was shady about his reason for the trip. In almost every sentence he uttered, there was a contradiction. Therefore, the police thought he was suspicious, especially when he wouldn’t answer questions about his luggage.
Alarm Bells
The police ran a background check on him and realized his passport was fake. Finally, they learned he was a convicted felon who had been released from jail. His documents were government-sealed, but this set off alarm bells.