Two Nazi flags were spotted on display from the roof of a high school outside of Dallas over the weekend, sparking an investigation.

According to the Heath Department of Public Safety, police responded to a report early Saturday morning and immediately removed the “antisemitic materials” that were displayed. Police said they’ve launched an investigation.

“We want to assure our community that we take this incident seriously,” police wrote in a Facebook post. “We will not tolerate this behavior, and we are committed to holding those responsible accountable.”

During a public meeting on Monday, school board member Grant DuBois condemned the flags and praised the students who initially reported them.

“The display of antisemitic flags on our campus is a hateful act that does not reflect the values of our district, period,” he said, according to local TV station WFAA. “We do not tolerate that as a school district. We do not tolerate that as a community.”