A father in Sutter Creek, California, chose violence Wednesday—literally—during an argument with a school teacher over indoor masks. The dad spotted his daughter walking out of Sutter Creek Elementary School with a mask on, as consistent with the school’s indoor mask policy. He then began verbally attacking the school’s principal, prompting a male teacher to intervene. His choice words became hard punches when the dad attacked the teacher, leaving the teacher bleeding and bruised, according to Amador County Superintendent Torie Gibson. The teacher was later taken to a hospital for treatment and released Wednesday night.

The attack prompted Gibson to send a letter Thursday to the community urging people to “take a breath, pause, listen and walk away if necessary” if they’re angry over COVID-19 policies. “Assaulting a staff member will never be tolerated on any school campus, and will be prosecuted to the fullest extent of the law,” Gibson wrote. “Remember, we are not the ones making the rules/mandates, we are the ones required to follow/enforce them if we want to keep our doors open and students at school five days a week.” Gibson told KCRA that the parent was banned from school property, and the district is considering pressing charges.