I think you did exactly the right thing. Had you jumped out of the bushes, beat shot, stabbed, sprayed him etc. The ensuing criminal and civil law suit would go something like this.
So Mr Smith why did you Jump out of the the bushes, and beat, shoot, stab and or spray young Joey? ( who buy the way is a wonderfull child) Well he tied a rope across my steps. Did you or anyone see him do that? You, well no. Were you hurt well no.
Now young Joey (wonderfull child that you are) what happened ? Well, (He gasping for breath, and sobbing) I don't know anything about any rope. I was just (pick one) lost, looking for the bathroom, trying to find my dog, etc.
When the crazy guy jumped out from behind the bushes and beat, stabbed shot and or pepper sprayed me.
Like D@M I am no wuss, and have seen some very ugly things. But a lot of this big talk is just that big talk. It just is not worth the risk.
Find who the kids were the guests of the next morning and talk to them, Call the police if you want. But don't ruin your life over something like this