Reviews of her by teachers. Just amazing.
http://teachervoice.com/principal-reviews/Brooklyn/P-S-90-Edna-Cohen-School/10-47416/
Not amazing. Either 1's or 10's, not much in-between. In other words, if you're part of her clique, she's golden. If you're not in her group, she's poison. I can guess the criteria for being part of her in-group.
I rather imagine the admin higher-ups are on this problem by now for a year or more, given the sharp cleavage apparent in the teacher ranks. Time they found out what is really going on here.