A man who killed five students and himself during a shooting spree at an Illinois college had stopped taking medication and become erratic in the last two weeks, buying two guns used in the bloodbath just six days ago, officials said on Friday.
He was identified as Stephen Kazmierczak, 27, a former student at Northern Illinois University where he returned to carry out Thursday's shootings, hiding a shotgun in a guitar case as he entered a lecture hall, police said.
His motive is not known, campus police chief Don Grady told a news conference. Nor were there indications he had any relationship with any of his victims who were mowed down as he fired more than 50 shots in a matter of seconds from a lecture hall stage, Grady said.
Local officials revised the death toll downward, saying Kazmierczak killed five students, not six as they had earlier reported, and wounded many more. In all 21 people were shot before he turned one of his four guns on himself.
"Apparently he had been taking medication" but stopped and had become "somewhat erratic" in the last two weeks, Grady said. He did not describe what kind of medication was involved.
"There were no red flags. He was an outstanding student, an awarded student" who was even "revered" by faculty and fellow students, Grady said. "A fairly normal, undistressed person."
Grady said the shooter had been enrolled at the University of Illinois at Urbana-Champaign in the central part of the state, far removed from Northern, a 25,000-student school 65 miles west of Chicago.
A federal firearms agent said Kazmierczak bought a shotgun and a handgun nine days ago in Champaign, apparently legally.
The Chicago Tribune reported that he had drawn notice in academic circles, helping write papers on self-injury in prison and on the role of religion in early U.S. prisons, work that earned him a dean's award.
'A very good student'
Kazmierczak "by all accounts that we can tell right now was a very good student that the professors thought well of," school president John Peters said in an interview on ABC's "Good Morning America."
"There is nothing in our system that he has had any counseling," he added. "Motive is the one thing that we're trying to pin down at this point. I really at this point have no sense of that. There is no note or threat that I know of."
Three of the students who died were 20, one was 19 and one was 32.
Terrified and bleeding, students fled the hall before the gunman shot himself on the stage in the latest in a series of shootings at US colleges and high schools.
Virginia Tech, a university in Blacksburg, Virginia, became the site of the deadliest shooting rampage in modern U.S. history in April 2007 when a gunman killed 32 people and himself.
Peters in a separate interview on CNN said the university had reviewed and improved its emergency response plans after the Virginia Tech shooting.
While universities traditionally have been "some of the most open institutions," he said, "events like this and Virginia Tech and others are forcing us to reconsider how we do things. I think that is unfortunate but necessary."
President George W Bush said he had spoken to Peters and told him "that a lot of folks today will be praying for the families of the victims and for the Northern Illinois University community. Obviously a tragic situation on that campus and I ask our citizens to offer their blessings, blessings of comfort and blessing of strength."
Illinois senator and presidential candidate Barack Obama in a statement said that beyond prayers "we must also offer ... our determination to do whatever it takes to eradicate this violence from our streets and our schools; from our neighborhoods and our cities."