A growing media campaign that has been hijacked by white supremacists made its way to South Pasadena High School on Halloween.

Posters reading “It’s OK to be white” were discovered on classroom and bathroom doors on the campus on Nov. 1.

School officials told the campus newspaper The Tiger that someone wearing a mask was captured on surveillance video putting up the signs. 

School officials removed about a dozen signs before school started the following day.

Posters with the same message turned up in at the University of Vermont and Champlain College, American River College in Sacramento, Duke University, North Carolina State University, Tufts University, the University of Delaware, the University of Denver and the University of St. Thomas in Minnesota, according to several media reports.

Posters bearing that slogan were also put up last year on Halloween at a high school in Maryland. Authorities there speculated the culprits may use Halloween because they can move around more freely while wearing a mask.

The slogan first appeared on the Internet in 2017 and was originally used to steer white Americans toward the political right. However, according to Newsweek, the slogan was hijacked by far right white supremacist groups, including neo-Nazis and former Ku Klux Klan Grand Wizard David Duke.

Richard A. Baker, president of the American Association for Access, Equity and Diversity, told insidehighered.com, an online publication that provides news, opinion and resources about college and university topics, that he believes the intent of the flyers “is to find sympathizers to the white nationalists’ cause” who may not be sympathetic to a swastika or other “traditional symbols of white nationalism or direct recruitment.”

The incident is being investigated by the South Pasadena Police Department.