Michigan Tech University is limiting access to its ROTC building for the rest of the spring semester after a threatening message was found in a bathroom.
A lockdown was ordered Wednesday afternoon after a cadet with the ROTC program discovered the note. It was found on the first anniversary of the massacre at Virginia Tech, where a mentally ill student killed 32 people.
University spokeswoman Marcia Goodrich said Thursday the building will be accessible only to staff, faculty and cadets until the semester ends May 2. A card-swipe system will let authorized users inside.
Goodrich says the Houghton university won't reveal the contents of the threatening note to avoid compromising the police investigation.
An e-mail notice was sent to students and employees.