According to a letter sent to parents on Sunday, district officials say they were also made aware of a large gathering of high school seniors over the weekend.
Organizers say the outdoor event was to honor a rising senior who recently died after a car crash on Interstate 295.
Senior Jordan Farr says while she was nervous about attending, she wanted to remember her friend.
"I really just went for that purpose and I know a lot of people went just for that, too," she said. "We all just kind of came together and we kind of just all forgot that we all didn't have masks on. We were just there for each other."
Once word of the gathering spread on social media, school officials decided to delay the start of in-person classes at the high school as part of a hybrid schedule from Monday to Thursday to conduct contact tracing with the county health department, saying several student-athletes have recently tested positive for COVID-19.
"Our immediate concern was to make sure that none of the students that we knew were in fact positive were in attendance," said Superintendent Joseph Bollendorf.
He says the decision was not meant to vilify the organizers or students who attended.
"The district has worked very hard to be able to be in a position to open our schools safely, but trying to maintain that is significantly challenging," he said.
Many families are anxiously awaiting the return of in-person classes.
"No matter what decision they make, somebody's going to be upset about it. I'm just looking forward to a little bit of normalcy if they can," said parent Karen Basu.
Board members from the club where the event was held said they took several precautions during the event, including temperature checks at the door. Students also had to have signed waivers, and masks were encouraged but not required because the event was outside.