Think there is a reason to be concerned?

This was a news story here a few days ago, and I found it disconcerting. A visiting student from Yemen at Purdue University left with two middle eastern men apparently to visit someone in the Detroit area. The student has not yet returned. I try not to be overly paranoid, but something about this made me wonder if it was just a random disappearance, or possibly something more? I guess all the news and warnings lately have made me jumpy. Here is the link...Purdue News