Details are beginning to emerge from another mass killing at a school by a young person. Some information suggested a young man interested in corrections, other information suggest he was being treated for mental illness.

Preventing these kind of tragedies needs to be a high priority effort by all of us. The solution can not be found by locking up everyone who might be violent, we can't afford that many jail cells. It must be based on how we raise and educate our children, not just academically, but emotionally. We can no longer afford to ignore emotion education.

ABC News

Stephen Kazmierczak, the 27-year-old who opened fire on a crowded Northern Illinois University lecture hall, killing five and then himself Thursday, was described as "fairly normal" and an "unstressed person" by NIU campus Police Chief Donald Grady.

But in the last few weeks his behavior had become erratic, according to Grady, and it is believed the Kazmierczak had stopped taking his medication. The chief declined to specify the type of medication the gunman was on.

Kazmierczak had served as a member of the NIU Academic Criminal Justice Association, was a teaching aid during his undergraduate years and in 2006 even received a Dean's Award from the sociology department.

In 2006 Kazmierczak was a co-author of an essay entitled "Self-Injury in Correctional Settings: 'Pathology' of Prisons or of Prisoners," in which an attached biography describes him as having just begun his graduate work at NIU.

Kazmierczak's interests are listed as corrections, political violence, and peace and social justice, according to the essay, and he had plans to co-author a manuscript on the role of religion in the formation of early prisons.

In another biography, apparently written by Kazmierczak for the Academic Criminal Justice Association's Web site, he pledged his commitment to social justice and his academic work.

"I've worked very hard as a student," the entry reads.

Kazmierczak worked as the Pirates Cove Childrens Theme Park in his hometown in 1995, according to the park's director. He had an acceptable employee record.

[..]Originally from Champaign, Ill., Kazmierczak had been a student at NIU in the spring of 2007, where he had majored in sociology. He had been studying at the University of Illinois - Campaign most recently, according to NIU school officials.

Grady said that those who knew him "revered him as an outstanding student" and had no inclination that Kazmierczak was capable of such carnage.

But law enforcement authorities told ABC News that Kazmierczak had likely planned the assault on the school for at least five days -- he had bought most of his arsenal, including a 12-gauge shotgun, .22-caliber pistol and a 9 mm pistol, at a gun store in Champaign, Saturday.

Another .45-caliber Glock semi-automatic handgun that was found on the scene has also been linked to him. He brought some of the weapons to campus in a guitar case, police said, and hid others underneath his jacket.

At approximately 3:15 p.m. Thursday, Kazmierczak -- dressed in black and armed with three handguns and a shotgun -- entered an introductory geology class and opened fire.

While students ran for cover and hid under their desks, Kazmierczak wounded 16 people, killed five others and then himself.

"The assailant began firing into the assembled class from the stage -- from the front," NIU President John Peters told ABC News.

"It didn't seem like he was aiming. He just raised a gun and shot immediately," said Paul Sundstrom, a student who was sitting in the class with his brother Kevin when the gunman opened fire.