If you think it falls into the correct category, call code enforcement. There are rules and restrictions each city puts into place that help keep it citizens safe from substandard housing and unsafe conditions. It will also cover too many people living in one residence (it does in my city anyway). I don't know what your problem is, but try code enforcement and they can guide you to the correct city office if there's is not the correct one.
Why do you care stop being jealous just worry about your own life stop getting into other peoples business