Follow-up on ?how did they know? I read the rest of the article. So why did the passenger tell anyone that he was carrying a gun? Was this a sting?
He was going into Japan. If Japanese customs catches you with a gun or drugs for that matter you go to a Japanese jail. He may have weighed the options and decided it was the lesser of 2 evils to be stopped as he got off and sent back to fight the charges in the U.S.