What prompts Chad's schoolteacher to knock on the Navidson's front door?

In school, Chad has been drawing disturbing pictures of his home, which prompts the teacher to think he might be a victim of child abuse. She checks on Daisy's pictures of home and finds they are nearly identical to Chad's. She decides to pay the parents a visit to find out what is going on and is so terrified by what she sees, she leaves and never comes back.