I'm just at episode 2, but I can say that:
- In episode 1 the strangest one was the student bumping into Joo Hyun and the teacher (the one sending message to "start" something - Now that I've seen more, also the Red Tumbler and the reaction of the student when Min was trying to keep the runaway still... I don't know, I think Ji Hoon (I'm not sure about his name) is definitely involved.
- In episode 2, isn't it Joo Hyun in one of the photos of Seok Joo? Protesting, in front of the prison. Also, she knows what Seok Joo said in court, so I think she is involved somehow (maybe just a fangirl or seeking revenge)
- Finally, the prison guard who tries to befriend Moo chan was suspicious.
Okay, I don't know yet xD