KARNS CITY — A bomb threat Tuesday at Karns City Junior-Senior High School was found to be a hoax, but not until after all 730 students and 80 employees were evacuated.

A student found the threat written on a wall of a bathroom stall in the high school portion of the building and reported it to the high school office around noon, touching off the evacuation and response by state police, said Superintendent Eric Ritzert.

Police found no evidence of a bomb and believe the threat was a hoax but are investigating the threat, Ritzert said. He said the threat was likely made by a student.

“It’s our intent to find out who did this and we will seek prosecution to fullest extent the law permits. It’s an ongoing investigation,” Ritzert said. “It is our assumption it was likely one of the students present today that made the threat.”

School district police, who are retired state police officers, are assisting in the investigation.

Teachers escorted students to the football field. Buses arrived and began taking students home between 1:30 and 1:45 p.m., he said. The normal dismissal time is 2:30 p.m.

“The threat was reported by a student and ultimately to the high school office and state police were notified, and responded to the scene. Students were evacuated. They were escorted to the football field by teachers until buses were staged for dismissal,” Ritzert said. “A search of the building was conducted and there was no physical sign of a bomb. We believe it was a hoax, but it was a specific threat so it was treated as real.”

Staff followed evacuation procedures that are practiced, he said.

Ritzert called the incident disheartening because it disrupted education and was upsetting for students and employees.

All Tuesday evening activities at the school were canceled, but classes will resume their normal schedule Wednesday, he said.

Both guidance counselors at the school will be available for students and the two other counselors in the district will be brought in if needed. Outside counselors can also be summoned if needed by students or staff, he said.

Ritzert posted a notice about the incident on the district website for parents and guardians. It says:

“As you are aware, a bomb threat was discovered at the High School today. We immediately notified state police and evacuated the building. State police worked with our school police officers to determine the threat was not credible.

“The safety of our students and staff is a priority at Karns City School District. The district takes all threats very seriously and will implement all appropriate disciplinary action under our student code of conduct and the Pennsylvania State Law.

“If you see or hear any disturbing statement involving our schools or our students, please immediately report it to local law enforcement and the school district.

“At Karns City School District, we have five school police officers, all of whom are retired state police officers, working in our schools. In addition, we have many other safety measures in place and will continue to strive to improve school safety in our district. If you ever have questions or concerns about school safety, please contact your child’s principal.”