If there is such a thing as a profile of a mass murderer, Steven Kazmierczak didn't fit it: outstanding student, engaging, polite and industrious, with what looked like a bright future in the criminal justice field.
And yet on Thursday, the 27-year-old Kazmierczak, armed with three handguns and a brand-new pump-action shotgun he had carried onto campus in a guitar case, stepped from behind a screen on the stage of a lecture hall at Northern Illinois University and opened fire on a geology class. He killed five students before committing suicide.
University Police Chief Donald Grady said, without giving details, that Kazmierczak had become erratic in the past two weeks after he had stopped taking his medication. But that seemed to come as news to many of those who knew him, and the attack itself was positively baffling.
"We had no indications at all this would be the type of person that would engage in such activity," Grady said. He described the gunman as a good student during his time at NIU, and by all accounts a "fairly normal" person.
"There were no red flags," Grady said. "He was someone who was revered by students and teachers."
Just last spring Kazmierczak was a success story, a sociology grad student here who'd earned a Dean's award for a paper on prison society, reports CBS News correspondent Cynthia Bowers.
Exactly what set Kazmierczak off - and why he picked his former university and that particular lecture hall - remained a mystery. Police said they found no suicide note.
Investigators learned that a week ago, on Feb. 8, Kazmierczak walked into a Champaign, gun store and picked up two guns - the Remington shotgun and a Glock 9mm handgun. He bought the two other handguns at the same shop - a High Point .380 on Dec. 30 and a Sig Sauer on Aug. 6.
All four guns were bought legally from a federally licensed firearms dealer, said Thomas Ahern, an agency spokesman. At least one criminal background check was performed. Kazmierczak (pronounced kaz-MUR-chek) had no criminal record.
Authorities responded quickly to the shooting; the first 10 police officers were on the scene in 90 seconds. NIU launched its emergency alert system - a carefully rehearsed plan developed after Virginia Tech - sending out e-mails and messages on Web sites to notify students that a possible gunman was on campus and they needed to find a safe area.
NIU Vice President Eddie Williams says his school learned a valuable lesson from Virginia Tech; still, he believes more drastic changes may be needed, reports CBS News correspondent Randall Pinskton.
One idea being proposed in nine states is allowing licensed gun owners - students or faculty - to carry weapons on campus. But many universities are strongly opposing that idea, saying more guns on campus would only increase the risk of more violence, Pinkston adds.
Kazmierczak had a State Police-issued FOID, or firearms owners identification card, which is required in Illinois to own a gun, authorities said. Such cards are rarely issued to those with recent mental health problems. The application asks: "In the past five years have you been a patient in any medical facility or part of any medical facility used primarily for the care or treatment of persons for mental illness?"
Kazmierczak, who went by Steve, graduated from NIU in 2007 and was a graduate student in sociology there before leaving last year and moving on to the graduate school of social work at the University of Illinois in Champaign, 130 miles away.
Army records indicate he enlisted in Sept 2001 and was discharged in Feb. 2002. He received an "entry level separation" which is neither honorable nor dishonorable, but rather uncharacterized.
"It was absolutely not due to bad conduct. It was an administrative discharge and we don't know why," Maj. Anne Edgecomb told CBS News.
Chris Larrison, an assistant professor of social work, said Kazmierczak did data entry for Larrison's research grant on mental health clinics. Larrison was stunned by the shooting rampage, as was the gunman's faculty adviser, professor Jan Carter-Black.
"He was engaging, motivated, responsible. I saw nothing to suggest that there was anything troubling about his behavior," she said.
Carter-Black said Kazmierczak wanted to focus on mental health issues and enrolled in August in a course she taught about human behavior and the social environment, but withdrew in September because he had gotten a job with the prison system. He recently left the job and resumed classes full-time in January, Carter-Black said.
His University of Illinois student ID depicts a smiling, clean-cut Kazmierczak, unlike the scowling, menacing-looking images of Cho that surfaced after his rampage.
NIU President John Peters said Kazmierczak compiled "a very good academic record, no record of trouble" at the 25,000-student campus in DeKalb. He won at least two awards and served as an officer in two student groups dedicated to promoting understanding of the criminal justice system.
Exactly what sort of career he planned for himself was unclear. But he wrote papers on self-injury in prison and the role of religion in the creation of early U.S. prisons. The research paper on self-injury in prison said his interests also included political violence and peace and social justice.
Speaking Friday in Lakeland, Fla., Kazmierczak's distraught father did not immediately provide any clues to what led to the bloodshed.
"Please leave me alone. ... This is a very hard time for me," Robert Kazmierczak told reporters, throwing his arms up and weeping after emerging briefly from his house. He declined further comment about his son and went back inside his house, saying he was diabetic. A sign on the front door said: "Illini fans live here."
A statement from the family of Steven Kazmierczak was posted on the door of his sister's home in Urbana, Ill.
"Our heartfelt prayers and deepest sympathies are extended to the families, victims, and all other persons involved in the NIU tragedy," the note read.
"We are both shocked and saddened. In addition to the loss of innocent lives, Steven was a member of our family. We are grieving his loss as well as the loss of life resulting from his actions.
"As a result of our family's extensive grief, we will not be making any additional statements to the news media. We respectfully request the media honor our family's wish and recognize our grief following this tragic event."
Neighbors in the brick apartment building in Champaign where Kazmierczak last lived were shocked to hear he was the gunman.
"It's not possible," said Maurice Darling, 80, who lives in an adjacent second-floor apartment. "He seemed to be much too nice."
He said the tall, thin and bespectacled Kazmierczak shared the apartment with a woman and neither showed any sign of anger or aggression. "They were friendly, agreeable - just like any neighbor would be," she said.
Chelsea Thrash, a 25-year-old waitress who lives with her 3-year-old daughter in the apartment directly beneath Kazmierczak's, said he was always up late and there was frequently a lot of "trampling" noise coming through the hardwood floor. She went up and knocked on the door once recently at 1 a.m. or 2 a.m. to request quiet and he said through the closed door, "Oh, I'm sorry - I dropped my weight."
"It's kind of creepy," she said. "I never thought someone in this tiny corner of southwest Champaign would ever dream of that, let alone carry it out, and have that above me and my daughter."
Kazmierczak grew up in the Chicago suburb of Elk Grove Village, not far from O'Hare Airport. His family lived most recently in a middle-class neighborhood of mostly one-story tract homes before moving away early in this decade. His mother died in Florida in 2006 at age 58.
He was a B student at Elk Grove High School, where school district spokeswoman Venetia Miles said he was active in band and took Japanese before graduating in 1998. He was also in the chess club.
At NIU, six white crosses were placed on a snow-covered hill around the center of campus, which was closed Friday. They included the names of four victims - Daniel Parnmenter, Ryanne Mace, Julianna Gehant, Catalina Garcia. The two other crosses were blank, though officials have identified Kazmierczak's final victim as Gayle Dubowski.
Students tell of terror and chaos in the large lecture room in Cole Hall, reports Bowers, when Kazmierczak, dressed in black and wearing a stocking cap, emerged from behind a screen on the stage of 200-seat Cole Hall and opened fire just as the class was about to end around 3 p.m., sending panicked students fleeing for the exits.
Tim Mayerbock, a guard on the football team, ran into the line of fire to save a wounded student.
"I seen him fall, you know, this guy was obviously head-hunting, so I grabbed him. I just tried to get him out of the way cause he couldn't do it himself," Mayerbock said.
Allyse Jerome, 19, a sophomore from Schaumburg, recalled how the gunman squeezed off more than 50 shots as screaming students ran and crawled for cover.
"Honestly, at first everyone thought it was a joke," Jerome said. Everyone hit the floor, she said. Then she got up and ran, but tripped. She said she felt like "an open target."
"He could've decided to get me," Jerome said. "I thought for sure he was going to get me."