KNOX, Pa. (EYT) — Authorities are investigating a bomb threat at Keystone School District.

According to district superintendent Shawn Algoe, someone wrote a threatening message on a bathroom wall near the high school gymnasium.

Parents were in the school around 7:00 p.m. on Sunday during music practice when one of them discovered the threatening message.

The message read: “There’s a bomb and bombs away.”

Algoe said it’s likely the threat was made on Saturday following basketball games being held at the school.

“We believe this occurred on Saturday when there were four basketball teams playing at the school,” said Algoe. “None of the teams were Keystone. Keystone just hosted the event.”

Algoe said the authorities were contacted immediately and the Pennsylvania State Police used bomb-sniffing dogs to search the school for explosives.

No explosives were found.

Authorities cleared the scene around Midnight.

The school reopened on Monday and is operating under its normal schedule.

“Today is business as usual, but of course, we have been vigilant because of the Parkland incident,” said Algoe.

“Thanks to PSP and for their efforts,” said Algoe. “They have a very difficult job to do, and I was very pleased with their response as well as the depths that they went to ensure the safety of our students.”

Parents were notified of the threat via an automated one-call message on Sunday evening.

No suspects have been identified.

The incident remains under investigation.

Stay with Explore for continuous coverage of this Breaking News story.