If you are the principal of a school, your highest priority has to be the well-being of students. Looks like he and other members of the school administration sat on this info for months. Problems don’t just go away, especially when your job is explicitly involved with the disciplining and protection of children.
A friend of 8 years stole a few dresses from me while we were out on a trip. They weren’t necessarily expensive, just cute sundresses that I had bought after saving up some money with my first big job. After returning home, I texted her to get one back because it was the dress I wore on my first date with my (now) husband and was sentimental. I was willing to part with the other ones. Her response was “Since I already have it with me, it would be easier if I just keep it and not have to find a way to get it to you.”
We lived ~20 minutes apart. After that, I was ghosted. She continued to wear the dress and post photos online, blocking me so that I couldn’t see, but other friends saw and reported back to me. Safe to say she was not invited to the wedding.