Yesterday Northern Illinois University in DeKalb joined the long and growing list of American campuses bloodied by active shooters.

Shortly after 3 p.m., a gunman identified by police as former NIU graduate student Stephen Kazmierczak stepped out of the shadows at the front of a large lecture hall and opened fire on a packed oceanography class with a shotgun and two handguns. Five students were killed and 16 wounded. The gunman killed himself before police could respond.

University officials say that campus police officers reacted to the shooting two minutes after the first shots.

Victims killed in the massacre have been identified as: Daniel Parmenter, 20; Catalina Garcia, 20; Ryanne Mace, 19; Julianna Gehant, 32, and Gayle Dubowski, 20.

At 3:20 p.m., the university posted a message on its Website telling students there had been a shooting on campus and that they should "get to a safe area." Most students already knew what was happening via text messages and phone calls from their friends. The all-clear was given by campus officials about an hour later.

The alleged gunman was an award-winning scholar who had left campus last spring. The Chicago Tribune and other media sources have reported that he may have stopped taking medication and was acting erratically before the shooting. At presstime, the reason that the accused gunman was on medication had not been revealed.

Witnesses told local media that the gunman, dressed in all black, broke into the large lecture hall through a side door behind the stage. He then emerged from behind the hall's projection screen firing a shotgun from the hip. He was also armed with two handguns. Investigators have recovered 48 casings and six spent shotgun shells at the scene.

Federal firearms agents say that the alleged gunman purchased the weapons legally about nine days earlier in the central Illinois town of Champaign.

About 25,000 students are enrolled at Northern Illinois University. Classes have been canceled indefinitely, but the dorms are open, and the campus has not been locked down.

NIU was also closed during final exam week in December after campus police found racial slurs and threats painted on a bathroom wall in a dormitory. The graffiti also referenced the Virginia Tech massacre last April in which 32 students and teachers were killed by an active shooter. Campus police do not believe there was a connection between this shooting and the graffiti, which shut down the campus for one day.

Alleged gunman Kazmierczak was a sociology grad student who specialized in criminal justice research. He won an award for his research into inmate self-injury in American prisons.

Investigators have not discovered a motive for the shootings.