Can we get a person in a co-op evicted for haring us & our neighbors?

We live in a co-op and have been hared by the woman who lives downstairs from us since October, when our 13 month old son started crawling. She started leaving nasty letters, all anonymous, on our door stating that we were causing cracks in her ceiling and breaking her ceiling fan. How a baby walking & crawling around can do that is beyond me. Our management company has been dealing with her haring us and various other shareholders for many years, as I've been told by the management company. I'm not sure that she's all there, mentally, and I believe she suffers from paranoid schizophrenia, but when she's off, she's dangerous. She called CPS on us and our case was recently closed because of an unfounded claim, but the only reason she called was to get back at us for having people in our home for the night. I found out today that she left a letter on my neighbor's door, stating that she knows I'm saying things behind her back and made a long list of fictitious derogatory things. In my book, that's slander and I should have some sort of serious complaint to bring against her, but everything is done anonymously. She has a very specific old style printer that would be easy to find if we had a detective in here, but my husband was told that the police consider this a dispute between neighbors and that we cannot do anything unless she threatens bodily harm, but I think this is worse. She must be mentally ill because she thinks it's completely okay to write us nasty letters pretending to be someone else. Sometimes it's a cousin of hers, sometimes it's residents on my floor and sometimes it's her. We're trying to talk to the board but we get nowhere with them, as they keep ignoring our emails. I'm wondering if there is some sort of petition or letter we, as residents, can get signed stating that she's been haring people for years & needs to be investigated and possibly evicted. Also, I was trying to figure out if I can have a restraining order taken out to prevent the ridiculous letters. (I live in Nau County in New York.) The fact that I have to deal with this to protect my son who goes to bed at 9:30 and she doesn't like running around is absolutely absurd! Please, any information would be helpful!