DEKALB, Ill. (CBS) — On this day four years ago, a gunman opened fire on a geology class at Cole Hall at Northern Illinois University, leaving five people dead before turning the gun on himself.

A memorial service for the victims of the 2008 NIU massacre will be held at 3 p.m. Tuesday.

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Meanwhile, Cole Hall has reopened after being shuttered ever since the shooting. It has been converted into an anthropology museum, and also features new high-tech classrooms and a computer lab.

The building went through a $6 million renovation.

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On Feb. 14, 2008, the geology lecture was in progress when Kazmierczak set a guitar case on the floor, pulled out a gun, and began shooting.

Five people were killed in the incident – Catalina Garcia, 20; Julianna Gehant, 32; Ryanne Mace, 19; Daniel Parmenter, 20; and Gaybe Dubowski, 20. A total of 21 others were injured.

Kazmierczak had already shot and killed himself by the time police arrived on the scene.

He had attended NIU previously, but at the time was doing graduate work at the University of Illinois at Urbana-Champaign. He had purchased the firearms he used in the shooting legally in Champaign.

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Following the shooting, then-Gov. Rod Blagojevich proposed that Cole Hall be demolished, but the idea was later rejected.