A teacher at a suburban Maryland high school has been placed on administrative leave after attending a private graduation party where students openly consumed alcohol and played drinking games, school officials said.

School system officials in Montgomery County began investigating the circumstances surrounding the May 16 party after the principal at Quince Orchard High School in Gaithersburg received a call from a concerned parent.

A video posted on social media appeared to show the educator playing beer pong with students, officials said.

“I want to assure you that we have taken the appropriate actions in conjunction with [the school system] and Montgomery County Police,” principal Beth Thomas wrote in a letter to Quince Orchard families. “I am deeply troubled by the failure of this staff member to exercise appropriate judgment.”

School officials did not release the teacher’s name, saying the matter was a personnel issue, and they did not say whether the employee was drinking at the time. The party came ahead of Quince Orchard’s graduation, scheduled for May 31.

School leaders emphasized the need to keep students safe at all times, especially during prom and graduation season.

Montgomery County Police Capt. Tom Jordan, a spokesman for the department, said police did not receive a call about last week’s party the evening that it happened, and charges are not being pursued.

Police are working with school officials to increase awareness about the dangers of underage drinking, Jordan said.

The principal’s letter reminded parents “of the essential need to be vigilant when hosting celebrations involving our students and to encourage all of us to reaffirm our pledge to keep all events involving our students alcohol and drug-free.”

The employee code of conduct does not explicitly prohibit school staff from attending functions outside of school involving students, and some students invite close teachers or coaches to celebrations, spokeswoman Gboyinde Onijala said.

“We ask employees to use appropriate judgment” and ensure their interactions with students are professional, she said. “You want to set an example for students, always.”