CHICAGO – A gunman opened fire with a shotgun and a handgun Thursday afternoon in a lecture hall at Northern Illinois University in DeKalb, killing people before shooting himself to death, authorities said.

NIU Police Chief Donald Grady said four victims had died.

At least 17 gunshot victims were taken to Kishwaukee Community Hospital in DeKalb, according to spokeswoman Theresa Komitis.

At TCU, senior advertising/public relations major Amanda Torres, one of 56 students from Illinois, said she lives just 20 minutes from Dekalb in Wheaton, Ill.

“One of my good friends goes there and I talked to her today,” Torres said. “Fifteen minutes (after I talked to her) we saw everything on the news so it was pretty crazy.”

Sarah Norris, a TCU sophomore early childhood education major from St. Charles, Ill., said though she does not personally have friends at NIU, she felt sad about the shooting.

“It’s heartbreaking,” Norris said. “It’s hard because it’s so close to home.”

At a news conference Thursday evening, NIU President John G. Peters said the gunman fatally shot himself, but he could not confirm anything about him or a possible motive. He said he 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.

The shooting occurred about 3 p.m. during a geology class in Cole Hall, in a large lecture classroom, authorities said.

“The shooter came from the front of the classroom where the instructor was, coming from behind a black curtain,” said Joe Grush, of the NIU provost office.

The shooter was wielding a shotgun and handgun, said Special Agent Thomas Ahern of the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives. ATF agents were assisting local authorities at the scene, Ahern said.

“We will be urgently tracing the firearms and learning the history of the weapons,” Ahern said. 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.”

Grady said at the news conference that the shooting “started and ended in a matter of seconds.”

He said the gunman was not believed to be an NIU student, but “he may be a student elsewhere.”

The campus will be closed at least through Friday, according to a statement posted on the university’s Web site. “Students can go to any residence hall for counseling,” the statement read.

Jillian Martinez, a freshman at NIU, said she was in the auditorium in Cole Hall when the gunman entered through a door to the right of the lectern and opened fire about 3 p.m.

“He just started shooting at all the kids,” she said. “He just started shooting at people, and I ran out of there as fast as I could. I ran all the way to the student center; when I got there I could still hear shooting (from the classroom).”

Martinez said the assailant was a white man and was carrying a large gun.

Officers responded to a call of shots fired on campus around 3 p.m., according to DeKalb County Sheriff Roger Scott.

NIU sophomore Geoff Alberti told his parents he was in the geology class when the gunman, carrying both a pistol and a shotgun, entered the auditorium-style classroom through an emergency exit. The shooter 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.

Most students dropped to the floor after hearing the first shot and then crawled out of the classroom on their bellies, his mother said. Alberti called his parents at 3:20 p.m. immediately after exiting the building.

“He was just frantic,” Marilyn Alberti said. “He said, ‘Mom, a guy just shot up my class.'”

Jason Meisner, Jeremy Gorner, Tina Shah and Jo Napolitano of the Chicago Tribune, staff reporter Christina Durano, and news editor Joe Zigtema contributed to this report.