I bet she will confront you & ask you what she did wrong? If so I would remain civil. You have to work with this person & this type of situation could sink you both down & make life testy for everyone where you work. I have run into this type of thing where I work. But you know what goes around comes around. It is a matter of time before someone higher up where you work will catch on or maybe they already have & will confront her. Your going to have to be patient & chew on nails, don't bring yourself down to her sick level.