Details probably missing because the parents want their names kept out of it, good luck with that...
But my guess is the teacher mentioned it to someone and was then advised that if only to cover her keister legally, she ought to make a formal report. Next thing you know, the doughnut boys are called up to defend the nation.
Someone’s probably going to get sued over this vast over-reaction. If the latte liberals take it in the pants through their municipal taxes, I won’t weep a tear.