BlueRose
Oh, this is a tough one, SS. You say that the administrator is aware that this person has malicious intent. Yet, at the same time, it would seem that the administrator is either turning a blind eye to it all or is in denial as to just how bad it is.
What is your gut telling you about this? Do you think that the administrator would be open to learning the full truth about this person? Has the administrator, in the past, when confronted with troublesome people been proactive in dealing with the problems? Or has she been a wuss and afraid to confront anyone?
If you do decide that the administrator is open to hearing the truth and will take appropriate action against this woman, then go ahead and talk to her. In addition, I'm sure you've documented these incidents to back up what you will tell the administrator.
So...basically, go with your gut on this one. Weigh the pros and cons. For example, if you go to the administrator and she decides to do nothing, will she at least keep what you told her in confidence? Or have you noticed that in the past, she is loose-lipped?
Best of luck with this awful situation. I can only imagine just how bad it is to have this woman in your work environment.
If possible, I would like to hear what you decided to ultimately do.