(CNN) On Thursday, the sound of bells rang out on the campus of Northern Illinois University to mark 11 years since five students were killed in a mass shooting.

One day later, two more members of that community -- a student and alumnus -- were killed in another mass shooting.

Northern Illinois University student Trevor Wehner and alumnus Clayton Parks were among those killed at an Aurora, Illinois, manufacturing business Friday in a shooting rampage by an employee who was being fired from his job.

They were killed a day after the Dekalb, Illinois, university's bells tolled five times at 3:06 p.m. to honor each of the students killed in a shooting on February 14, 2008.

That day, a former student opened fire, killing five and wounding more than a dozen others before killing himself.

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