The saga of the Scary Cats
I just spoke with the complainant again and she confirmed that it was the black and white cat that she thought tried to attack them. She also mentioned he is very vocal. I explained that he seemed very friendly and perhaps she may have misinterpreted his friendliness as being aggression. She says she will call me if there are any more problems. The woman does not live in the block of flats anyway, but she says she goes by every day.
I found that someone on the fifth floor has a cat that is unsterilised and the un-neutered male goes up to 'visit'. I advised the person to sterilise both cats and not to feed the male upstairs.
As for the other block where she saw the other scary cat, I found three sterilised cats. They have a caregiver and are very friendly which may have scared the woman as well. Let's hope this settles it.