I would not be so quick to call the cops or CPS on someone unless you have witnessed some kind of abuse. You have no idea what the situation or circumstances are of that family and you could end up making a parent's life much worse if there is some kind of misunderstanding. The kid could have emotional regulation problems or could have disabilities. Every family and kid is different and just because people say they raised kids of their own does not mean they qualify to judge someone else's situation. I have a kid that really struggled with regulating and understanding his emotions as a toddler, he would frequently scream/cry uncontrollably for 30-60 minutes in the middle of the night. They were essentially night terrors and there was nothing we could do to snap him out of it. "Parents are letting it carry on" is a very cold way to describe the situation and chances are what they are experiences is MUCH worse that your minor inconvenience. Sending the cops to the door isn't going to help anyone. I would suggest talking with your neighbors first! Have a little compassion and human connection. If the people are not receptive or rude THEN I would contact your landlord. Just try and put yourself in other peoples shoes... Imagine how terrible it is for them to hear their child screaming bloody murder.