I don’t want to sound like I’m defending this killer. He absolutely should go to prison for the rest of his life.
But in reading further articles, it sounds like the guy did complain about the noisy kids, and was told, probably multiple times, “Yeah, kids scream when they play. They’re kids, leave them alone.”
(I don’t know whether the guy actually talked to the parents of this girl or not. Not that that is any excuse at all for what happened.)
I must say, this reminds me of a thread I once posted here. In it, quite a few dopers responded with, “Kids are loud. Suck it up. You sound mean and bitter. What do you expect at an ice cream parlor?”
Just sayin’. Be careful whose opinions you brush off. There’s a lot of psycho nutjobs out there.