Neighbors fucking while their kid cries

It's currently 2am and I hear their 3-4 year old screaming.. has been going for 20 minutes now. No one is comforting. Why? Because they are having LOUD sex and moaning and talking about it while this baby cries.. they have an older child who is around 8 as well that shares a room with this baby.. this couple ignores their baby constantly and screams / throws crap at eachother and hits eachother all the time in front of these two kids. She screams at her baby to "shut the fuck up" on a regular basis.
What the hell should I even do?