let me help you a little first thing they do when you're a suspect is they take your passport they will give it back to you when they are done now if you go to the United States and it turns out they need more questioning you will have to come back cuz they will put a warrant out for your arrest in the statesFor sure, as a side note some other American suspects do things and get away with it including just last month, it may just have to do with how fast one can get to the airport putting them out of reach of the system. They may have to release him soon, nothing concrete seems to be sticking so far besides suspicion.
If he did, he ain't telling, yet the world is watching (no easier way to get out of it quick than by promptly exposing beating/duress etc)