Too close - need suggestions

So...I have been associated with a place for a number of years either as a student, employee, or instructor. Another person has been associated with the facility and its Administrator since 2001. The person inquestion is also an employee of the institution that runs the facility.

The person in question is one of the most venomous people that I have known and makes it her business to worm, wheedle, cajole? And manipulate her way into gallery shows, teaching (non-credit) positions, studios, and the like. My situation is this: this person is deliberately undermining the Administrator and openly "supporting" people who have caused trouble at the facility. The person in question has a key to this facility, comes and goes at will, entertains various sexua| encounters after hours, and uses her position as a "facilities and maintenance" employee to enter this facility and cause maintenance issues whenever she gets angry with the Administrator or anyone else associated with the facility that she believes to demonstrate loyalty or support for the Administrator.

I don't think that the Administrator is aware of just how much damage this person is attempting to inflict, although she IS aware that this person in question has malicious intent. Yesterday, the person in question came into the facility for whatever reason (facility is closed until the semester starts in January) and launched into a tirade about everyone at the facility with special venom reserved for the Administrator. Now, had this person not become involved with the Administrator and facility in 2001, she would never have been exposed and introduced to an artistic community or been able to wheedle her way into the situations that I mentioned above.

Should I speak openly with this Administrator about the absolutely viscious things that this person is saying, or just let the whole thing fall as it will? Tweet