You are in the position that you can do things legitimately. You have the upper hand already.
Since you are in the supervision postion, it is your responsiblity to restore order in you group. If you don't do, it nobody else would.
You should also have other people on your side too.
Keep up the documentation. When you catch her do something, you can send an e-mail to her to ask her why she did it and tell her not to do it again.
Don't give up. Don't be a quitter. All cards are on your side.
Since you are in the supervision postion, it is your responsiblity to restore order in you group. If you don't do, it nobody else would.
You should also have other people on your side too.
Keep up the documentation. When you catch her do something, you can send an e-mail to her to ask her why she did it and tell her not to do it again.
Don't give up. Don't be a quitter. All cards are on your side.