That woman is dumb. Authorities are indeed incompetent to pursue this further, but those two are unrelated. If either of those were not true, dumb thing would not have happened — as humans, we are all in this together, and it's all of our responsibility to do better. That neighbour included.

If she was worried about a child, she should have accompanied them home.

Next time, she'll send police over when a kid can't watch more TV (or go to a party, or eat more sweets, or...) and ends up crying her guts out: hey, she's worried about children's welfare. I would be having police at my door almost every other day with a neighbour like that.