The shooting occurred about 3 p.m. during a geology class in a large lecture classroom in Cole Hall, authorities said. The gunman, who CNN has identified as Steven Kazmierczak, entered through a back door and came through a curtain behind the stage before opening fire on the students.
"The assailant began firing into the assembled class from the stage," NIU President John G. Peters said at a news conference Thursday evening.
"Eyewitness accounts describe a very brief rapid-fire assault that ended with the gunman taking his own life."
Four of the victims who were killed were female, and one was male, Peters said. They were all undergraduate students. The wounded included 15 undergraduate students and one graduate student who was acting as a teacher's assistant, Peters said.
According to The Washington Post, four of the deceased have been identified as Catalina Garcia, 20; Julianna Gehant, 32; Ryanne Mace, 19; and Daniel Parmenter, 20.
Four, including the gunman, died at the scene, and three died later in a hospital, Peters said.
The gunman was a sociology graduate student who was enrolled in classes at NIU last spring but was not currently enrolled there, Peters said.
Authorities were not releasing his identity Thursday night but said they were not aware of any criminal history or violence in his past.
The gunman was found dead on the stage of the lecture hall, NIU Police Chief Donald Grady said. The shooter had a shotgun, a Glock pistol and one other small-caliber handgun, with ammunition still left in both handguns, Grady said. He said gun magazines were found "all over the floor."
"We believe there was only one shooter," Grady said. The shooting was "over in a matter of minutes," he said.
Peters said the motive for the "senseless tragedy" was unknown, but authorities had "no reason to believe" it was related to threats found on a bathroom wall on campus in December. The threats made reference to the 2007 massacre at Virginia Tech.
Classes will be canceled at least through Friday, Peters said. Students can go to any residence hall for counseling.
"We're advising them to remain calm, to seek counseling and support services," Peters said. He said the lecture hall remained an active crime scene Thursday night, with Illinois State Police, FBI and agents from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives all assisting DeKalb County authorities.
"We will be urgently tracing the firearms and learning the history of the weapons," said ATF Special Agent Thomas Ahern. He said agents will run the weapons through a national tracing center to "learn where they came from and how the shooter came to possess them."
Sophomore Geoff Alberti told his parents he was in the geology class when the gunman entered the auditorium-style classroom through an emergency exit. The gunman did not say anything before opening fire on the class, he told his parents.
"He said at least 20 rounds were fired," said his mother, Marilyn.
In December, the university was placed under a security alert through the end of the semester after police found threats on a bathroom wall that included a racial slur and references to the Virginia Tech shootings.
Two separate messages were found by a student on a restroom wall in the Grant Towers D complex that read that "things will change most hastily" in the final days of the semester, university officials said at the time.
You might be interested in...- Former Hokie football player arrested
- Column: Celebrate victories of summer grads
- Tech Department of Recreational Sports
