Officials at Western Illinois University said nearly 45,000 alert messages were sent to students and staff after a shooting threat Wednesday on the Macomb campus.

More than 5,000 text messages, 17,000 voice messages, and more than 22,000 e-mails were sent within an hour of finding a letter that read, “There will be a shooting today all around campus. Make the right decision. Ban. Bang.”

The university did not cancel classes on Wednesday because officials wanted to “underscore that such threats will not be tolerated.”