GRAND RAPIDS, Mich. (WOOD) — A threatening voicemail led to a shelter in place order at Grand Rapids Christian High School Monday morning.

The superintendent tells 24 Hour News 8 the school took precautions as soon as students arrived Monday morning, after administrators discovered the threatening message, which was left over the weekend.

The superintendent says their school worked with Grand Rapids police and a security consultant to investigate the threat, which turned out to be false. The shelter in place order was lifted at 10:30 a.m.

The superintendent says the threat is similar to a message sent to East Grand Rapids High School.

It’s unclear who is responsible for the threat.