THREE RIVERS, Mich. (WOOD) — One person has been arrested for a threat made against Three Rivers Middle School, the district said.

In a letter to parents on Monday, Interim Superintendent Nikki Nash said St. Joseph County Prosecuting Attorney David Marvin had notified her that an arrest had been made.

The district closed Monday as a precaution after the Three Rivers Police Department found the threat, made against the middle school by a local 54-year-old resident. The resident had called a local Kalamazoo news station to report he was going to “shoot up” the school, Michigan State Police said. The news station reported it to MSP.

The threat was determined to be “not credible,” according to an email sent to parents from the district.

“The staff at Three Rivers Community Schools constantly strive to keep our school safe. We have internal processes and procedures in place, and frequently run school safety drills as required by the State of Michigan. Threats coming from outside the school community pose a different challenge, so we are highly dependent on local law enforcement to keep our students and staff safe,” the email sent to parents on Monday said.

The district is encouraging students, staff and the community to “be observant and let school officials know if they see to hear something concerning.”

In Newaygo County, a staff member at Newaygo Public Schools received a phone call on Friday from a person who made a threat to the district. Law enforcement investigated and determined it was safe for the district to remain open on Monday, according to the superintendent.