I do not know how people can do anýthing like this, but I do know how they get away with it!
On various occasions when, as a teacher, I have suspected something has been seriously wrong in a pupil's home, I have been told, quite rudely, not to intefere both by head teachers and others.
If you go to the police and they too treat you as an interfering busybody, you do tend to give up, unless you can find something that is indisputable proof that a child is being ill-treated.
Perhaps we need to find a way to act on our suspicions, although I can well see that that could lead to false accusations that would be damaging in themselves to the children we would like to help.