A gun belonging to an off-duty police officer was “inadvertently” left in a bathroom Monday night at Eastport-South Manor Junior-Senior High School, the district said Tuesday morning.

According to the school district, the discovery was made by a custodian around 6:15 p.m. and was immediately reported to building security, school administrators and then Suffolk police.

After an investigation, Suffolk police said the gun was left behind in the bathroom by an off-duty police officer who is also a parent of a student at the school.

“The off-duty officer returned to the restroom area and shared the information with our security officers,” a release from district reads. “The parent cooperated with our security team, as well as with the SCPD when they arrived on the scene for their investigation of the security situation.”

In a letter to the school community, the superintendent said that the off-duty officer is a member of the Board of Education who was at the school for a BOE special session meeting and came directly from his job.

The superintendent says the entire issue was resolved within about 15 minutes.

The letter went on to say in part, “School safety and security remains our district’s top priority and we assure all families that we take these matters very seriously. I once again wish to thank our security team, the Suffolk County Police Department and all individuals who assisted with last night’s isolated incident.”