Glendora police responded to the school in the 1600 block of E. Foothill Boulevard around 12:50 p.m.
Erin Sims, 49, allegedly pushed and shoved a student who she claimed was being rude to her, police said.
"I will f--- you up if you do that again," Sims, who allegedly knows the teen, could be heard yelling. She then grabs the alleged rude teen's shirt and attempts to take him to administrators to be punished.
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Cellphone video then shows Sims' son using one of his crutches to hit the alleged rude teen in the back. That's when the brother of the alleged rude teen comes to his defense, escalating the incident.
Teachers and administrators heard the yelling and came out to break up the scuffle. Sims was then arrested.