Subsidized housing tenant harassed by neighbor

[Jess Hewitt]

I have a long time tenant who has been on a hosing voucher for years and I have watched her turn her life around over the years.  She takes great care of the condo.  She even bought tools to change the AC filter every three months.  She has studied hard to get a job and now has a career for herself to support her son.  However, she is being harassed by a neighbor who discovered she is receiving a subsidy for housing.  The neighbor has installed security cameras in the hallway to monitor my tenant and even questions my tenants guests.  My tenant just bought a car so now the tenant is harassing her about using the stairwell instead of the elevator as the stairs are closer to her parking spot.  The neighbor has called the police when my tenant has told her to leave her alone in a not so nice manner.  My tenant is a young women but raised by a strong mother who taught her to stand up for herself.

The neighbor is intent upon getting the HOA or me to boot my tenant out. We offered to meet with the neighbor at the HOA management office but she declined. After several years of these complaints the HOA has told the neighbor that they will do nothing. She has called the housing authority but they will not take action. The neighbor has left me messages and emails about how I will be responsible for any harm to come to her by my tenant and that she will sue me for any damages. I have blocked her number and email.

I really want to protect my young tenant and her son.  The other neighbors are all warning her and she is worried about what will happen next.

Is there anything that a landlord can do to stop another condo owner from harassing the landlord's tenant?  I am ready to call my attorney but I wanted to ask other landlords their advice.  What legal steps can be taken to stop the harassment.