They did this, most likely, by searching their luggage which was found to contain:

I have searched his luggage and found nothing.

It was some minutes before they could get around to searching Isabella's luggage.

He searches the party's luggage, and finds a sealed metal box, obviously a bomb.

The girl's mother remained unaware of the situation as she seemed to be frantically searching her luggage for something, so he decided to speak up.

I told her I had no idea where it was and even offered to let them search my luggage.

They even searched his luggage before the party was allowed to go through.

He gave them permission to search his luggage, and the officers found cocaine.

They then asked to search Place's luggage, but Place declined to allow the agents to do so.

Why did they want to search all my luggage at the airport? Do I look dishonest or what?