Students at the elite Washington, D.C., prep school Sidwell Friends projected swastikas on to a screen during a presentation on Wednesday, the school said.
The school is famous for its numerous high-profile alumni, including the children of several presidents.
On Wednesday, students were gathered for a presentation about OnSide, a student-run group that builds community among refugee children in the Washington area through soccer games. At the end of the program, students played an online learning game called Kahoot, in which they used their phones to answer questions that were projected on to a large screen.
Among the usernames projected on to the screens were two that included swastikas and several that were racist toward Asians and Native Americans, Bryan Garman, the head of the school, told parents in the letter. The projection was turned off quickly once school officials recognized the images.
“I am disappointed, dismayed, and deeply sorry that such an incident could take place at our school,” Garman wrote. “Racism and anti-semitism will not be tolerated in this community.”
The school has launched an investigation into which students included the racist language and swastikas into their usernames, Garman said.
HuffPost first reported the events at Sidwell Friends. Ellis Turner, the associate head of school, confirmed the incident to TIME and provided a copy of the letter sent to the families of students.
It’s not the first time the school has dealt with the presence of swastikas — in November, an unidentified person drew a swastika on a whiteboard after a teacher gave an etymology lesson on the naming of the Nazi party, the Washington Post reports.
Sidwell Friends is one of the most elite schools in the U.S., counting among its alumni Chelsea Clinton and Malia Obama. School tuition costs about $42,372.
Correction, March 8
The original version of this story misstated the status of the group OnSide. It is a student-run organization, not a registered nonprofit.