I had a bully in a grade 5 class I was subbing for two weeks. Fucker stabbed my hand with a pencil. I kept sending him to the office and staff wouldn't do shit about it. He would come back to class 5 minutes later and start shit again. I told the class I would keep them all in for detention every day because of the bullying. They turned on him.
The twist of "I had a bully in a grade 5 class" followed by "that I was subbing for two weeks" is just 
First a 5 year old pushes over a grown man. Now a 5th grader is the bully of the substitute teacher. Won't somebody stop these children from terrorizing these adult men of RE?
Subs have a tough time establishing classroom management. No matter the situation, the students will outnumber you and if one kid has bad intentions and doesn't want to follow the rules, then sure, you will have a more difficult time than you should.
That said, of fucking course they sent the kid back. If you have no documentation on why you sent him in the first place, the office staff or Dean of Discipline/Administration will have no idea why he's there in the first place and will send him/her back to the classroom. It's illegal to deprive an student of their education and how they can learn if they are not in the classroom! If the student really did stab a teacher with a pencil, then that's at least a suspendable offense, and should be written on a referral notice, and
directly reported to the administration staff. At least in California, it's illegal to hold students in after school detention after 15 minutes, and threatening everyone to punish one kid, that's just an asshole move. I haven't even gotten to the fact that most schools nowadays are trying to push Positive Behavior Intervention Support systems (PBIS). If I was a full time staff member or Administration, and I heard he pulled that shit, I would tell him he is not welcome to be at my school anymore, tell HR to take him off the rotation on my school. What the hell.
