Seaford Middle School was deemed safe for students and faculty after a search Wednesday by Nassau County police, a police spokeswoman said.
The school was evacuated for nearly three hours after officials found a written threat in a bathroom, police said.
Police said they could not immediately provide details of the threat found at the school, but said it was reported by a school administrator at 9:35 a.m. and the building was evacuated as a precautionary measure.
A police spokeswoman said the school was deemed safe at 12:19 p.m., after a search by police. Students were then allowed to return to class, she said.
School district officials did not respond to requests for comment on the reported threat.