Sounds like more than just walking on the lawn.
Yeah, I'd say that there was probably some vandalism prior to this...messed with his flags, perhaps.
Doesn't justify shooting the kid, unless he was to break into the house, of course.
When I was growing up, if the neighbor told me to stay off the lawn, I DID! Back then, he could just come out and paddle my behind...then my Dad would do the same when I got home!!
Different times we live in...no one respects others' property.
I suppose it is possible but I sure wouldn't take the murderer's word for it.