Kid Held down in Sewer by Another

Yesterday I saw what undisciplined children were really like and it made me sick to my stomache. I'd like some advice before I actually get into trouble or stand by and watch something so sick ever again.We have tons of trees losing their leaves around here, so much you could pile a few children under it and never know. The leaves can go up to your knees in part of the cul-de-sac on our street.