MACOMB, Ill. (AP) -- The campus at Western Illinois University is quieter than normal after an employee at a nearby apartment complex found a threatening note saying there'd be an on-campus shooting today.

Graduate student Jessie Kallman says the Macomb campus is normally bustling in the afternoon. But she says relatively few people could be seen around the 11,000-student campus today.

Students could choose whether to attend classes today. And more police are on patrol.

Kallman says she feels safe and attended classes. But she says the note frightened many of her classmates and most decided to stay home.

WIU activated an alert system at around 9:30 a.m., shortly after the note was found. It informed students by text message and e-mail about the threat.

Police are investigating and say no suspects are in custody.