Criminal Minds S9 Ep2 - "The Inspired (Part II)"
When they make arrests at the end:
There seems to be some difficulty over whether they have Jesse or Wallace. They use his learned nervous tick as a differentiator and arrest him accordingly.
Why would they need to do this?
Surely they could just ask him questions that Jesse would know the answer to (e.g. who are these pictures of? What happens in a normal day at work?) and demonstrate it was Wallace by his lack of knowledge of Jesse's life? Also, the BAU would knew he suffered from hallucinations, if they kept him talking long enough he would eventually give himself away.
Perhaps there is there some aspect of the American legal system that I am not familiar with? Or did miss something in the episode?