Sleepy Hollow Middle/High School was put on lockdown Friday afternoon after authorities say a threatening message was discovered.

Public Schools of the Tarrytowns originally released a statement on Facebook about the situation, saying in part, “A message threatening a school shooting was written on a high school classroom whiteboard when a teacher returned for class.”

The message prompted the school to go on lockdown and then lockout shortly after.

According to the district, police determined there was no immediate threat to students and staff at Sleepy Hollow Middle/High School. Afterschool activities were canceled and students were released with a controlled dismissal.

News 12 is told the lockdown lasted for nearly two hours as a precaution with students being dismissed after 3 p.m.

Evelin Chacha, a 12 grader at the school, believes people shouldn’t toy around in such situations.

"I just think that people shouldn't joke around with this stuff anymore. Everyone knows what every other state has been through with these shootings and they wanna make a joke, writing on the board knowing that it can affect everyone in our school,” says Chacha.

Once the lockdown was lifted, some parents felt a sense of relief. News 12's Carol Wilkinson caught up with a parent who shared her concerns.

"I don't feel like it's over, unfortunately. That kind of threat is not OK…” says parent Mistrella Murphy.

The district said in a statement to the school community that Sleepy Hollow police are working to identify a suspect.

The investigation is still ongoing.