Have you ever had a bad neighbour?

I hesitate to call her a bad neighbor, because she was a really good neighbor until she wasn''t. We'd been close for almost ten years. She was blind and had an adult son who was learning impaired, and she babysat for my daughter and sometimes I took her son to work in bad weather, or took both of them out to dinner. I did not realize she was paranoid schizophrenic until the Sheriff called one day to say she had reported my husband and I for torturing her son with lit cigarettes and stealing his money and hers. It was pretty upsetting, putting it mildly. It got worked out, but still leaves a bad taste, y'know?