He was an immigrant- they can question immigrants at any time.
Was he here in the country illegally? Syrian ‘refugees’ rarely had good paperwork.
If he was not a citizen then he does not have the same rights as citizens, no matter what the liberal media say.
He immigrated as a child. The family came to the U.S. over 20 years ago. The suspect is 21. So I doubt he could have been interviewed at that point.