how does this action result in her being fired? ...Seriously, would have someone work for you that has illustrated she has no respect for anything but her challenging authority? You are the boss, she has already said YOU need challenged. YOU say “Do not steal office supplies”, so she walks off with all the toilet paper in the lady’s room, steals three reams of copying paper and has the camera operator punch her in and out while she never shows up for work. After all, she is just challenging authority.
ISTR she did this on company time. See earlier threads on the subject for details.