Not exactly a theory, but a question.

At the end of the extended preview (http://youtu.be/gEXVZcADxC8), when PJ states "He's one of them", seeming shocked, could he be referring to Cho as a member of 'Tyger, Tyger'? He always wears short-sleeved shirts, which could've made it feasible for his tattoo to be revealed if in a fight with Kira Tinsley. It could all have been just a setup with her, and he is the one passing on info.

Also, Ron seems to be talking to Rigsby about the suspects, how come?

I can't wait for next Sunday!