Terrible story! Yes, children can be evil. I suppose it’s somewhat rare but I’ve met these kinds of kids myself.
do you remember the 12 yo boy who killed the 6 yo neighbor girl a few years ago
he claimed they were wrestling
she was a tiny girl he was a big kid...
at the time people said 12 yos are too young to be murderers, plot a murder or evil etc
from my own experience I knew that was wrong
I believed he could and would deliberately kill with no mercy...
Just like that girl did to my little daughter...
BTW my daughter is now in her 30s and married with beautiful children of her own...
Happy ending but it might so easily have not been...