Disturbed

I am so disturbed by this family who lives across our house. I seldom see the kids' parents at home because both of them are working. What bothers me is the way the parents treat the kids, I think they are being physically and verbally abused by their own parents, well, not that brutal but beating a child so hard for me can be a sort of abusing a young child's mind and body. One time I heard the mom shouting at her 10-year-old son, asking him to leave the house and to never come back again. How can you say that to your son? How can you tell something that would impose to a child that he is no longer wanted in that house? That his mother doesn't care if he leaves the house? There is no week that I will never hear them beating their children and I would be tempted to look outside my window to check if the kid's are still doing okay coz believe it or not, they beat their children sometimes in their garage and anyone who passes the house can clearly see them. I must admit the kids are hard to deal with, usually they are left with their old grandpa looking after them and I sometimes hear them saying really nasty words against their grandpa. I myself was a victim of their behavioral problems. Our garage right now has only one parking and while hubby's car is parked inside, mine is parked in front of our gate, they used to harass my car, add some scratch on it and put something in the key hole. They used to ring our door bell and hide whenever we open the gate to see who was ringing the bell. One day I got pissed off, after so many times of ringing our bell, I decided I will confront them. I waited for them to come and I caught them. I talked to them, asked them to stop and told them that I don't want to tell their behavior to their parents coz I don't want them to get hurt. After that, they never touched my car nor ring my bell again. I thought, maybe the reason for their behavior is because of parents who gives them less attention and because of the physical and verbal abuse. Disciplining a child is good but when do you know when you already hit the boundaries of proper discipline and physical abuse?