If there are any locals here, they need to calmly send a letter (snail mail) to each member of the school board, explain the situation, and demand that the teacher be removed from the school system.
That letter should be followed up a week later to the home phone of the school board member, polite but firm.
If that does not work, then follow up with a snail mail letter explaining the history to each school board member letting them know you will be voting against them and will be getting all your friends and neighbors to vote against them.
Ditto for the phone call a week later.
Ignore any excuses they give you, just keep on trucking...
This stuff works!
“This stuff works!”
150 angry parents and voters showing up at the next school board meeting would also have an impact.