UPDATE:

DAVISON, MI - City and township police officers posted up outside and inside a Davison school building after messages of a threatening nature were spotted online by community members.

In an April 10 letter by Davison Community Schools Superintendent Eric Lieske to parents and guardians of students, he said "several concerned parents and community members" observed several "very aggressive, threatening and intimidating social media posts" directed at the district and building administrators.

Students at Davison Middle School and Hahn Intermediate School, which share a building off Dayton Street, were placed in secure mode around 1:40 p.m. Tuesday afternoon per the district's safety protocol.

Michelle Edwards, Davison schools spokeswoman, said the district operates in secure mode each day - with doors locked and visitors identified prior to being let into buildings.

She pointed out during Tuesday's incident "as an added precaution we kept students in classrooms with the exception of during passing time - which included extra supervision - as well as having a police presence in the building."

Lieske noted police have been "actively involved in the case" and stayed on site throughout the day along with the district's school security officer.

"Please know that the district and law enforcement take matters such as these extremely seriously," he said. "The safety of our students and staff will always continue to be our top priority."

Calls by MLive-The Flint Journal to the Davison City and Davison Township police departments for additional information were not immediately returned.