(CBS/AP) The man who gunned down five people at Northern Illinois University in a suicidal rampage became erratic after halting his medication and carried a shotgun to campus inside a guitar case, police said Friday.
The man, 27-year-old former student Stephen Kazmierczak, was also wielding three handguns during Thursday's ambush inside a lecture hall.
Two of the weapons - the pump-action Remington shotgun and a Glock 9mm handgun - were purchased legally less than a week ago, on Feb. 9, authorities said. They were purchased in Champaign, where Kazmierczak was enrolled at the University of Illinois.
A spokesman for the federal Bureau of Alcohol, Tobacco, Firearms and Explosives said the other two guns were also legally purchased and traced to the Champaign gun shop, but the ATF was still determining when Kazmierczak picked them up.
Kazmierczak had a valid Firearm Owner's Identification Card, which is required for all Illinois residents who buy or possess firearms, authorities said.
The gunman's father, Robert Kazmierczak, briefly came out of his house in Lakeland, Fla., to talk to reporters.
"Please leave me alone. I have no statement to make and no comment. OK? I'd appreciate that. This is a very hard time. I'm a diabetic and I don't want to go into a relapse," he said before breaking down crying.
He then went back inside his house, which has a sign on the front door that says "Illini fans live here."
President Bush talked by telephone with NIU President John Peters and said people will be praying for the families of the victims and for the Northern Illinois University community.
Campus Police Chief Donald Grady said investigators recovered 48 shell casings and six shotgun shells following the attack in Cole Hall. The gunman paused to reload his shotgun after opening fire on a crowd of terrified students in a geology class, sending them running and crawling toward the exits. He shot himself to death on the stage of the hall. Sixteen people were injured.
Kazmierczak, whose first name was earlier listed as Steven, was taking some kind of medication, Grady said.
"He had stopped taking medication and become somewhat erratic in the last couple of weeks," Grady said, declining to name the drug or provide other details.
Correcting information his office released earlier Friday, DeKalb County Coroner Dennis Miller said five students, not six, were killed in the rampage, in addition to the gunman. Miller said the higher victim total was the result of confusion over the fate of a patient taken to another county for treatment.
"There was a miscommunication," Miller said.
The motive of the killer, who graduated from NIU in 2006 but was a student there as recently as last year, was still not known. Grady said Kazmierczak was an "outstanding" student while at NIU and authorities were still trying to determine why he would kill. There was no known suicide note.
"We were dealing with a disturbed individual who intended to do harm on this campus," NIU President John Peters said.
Witnesses said the gunman, 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. Officials said 162 students were registered for the class but it was unknown how many were there Thursday.
Students tell of terror and chaos in the large lecture room in Cole Hall, reports CBS News correspondent Cynthia Bowers, when the gunman 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.
"He just walked out on the stage and started shooting," recalled senior Sheila Cosgrove. "He shot the teacher first and just kept shooting."
Cosgrove was in the fifth row of the geology class when the gunman started targeting students nearby. Her eyes remained fixed on him, even as she tried to get away.
"I felt his glare on me," she said. "I saw the fire from the shotgun and I tried to run for my life."
"It was a huge gun, like a shotgun," said Desiree Smith, a senior. "I could see the puffs of smoke. I kept thinking, 'Oh God, he's going to shoot me. Oh God, I'm dead. I'm dead. I'm dead.'"
Smith dropped to the floor near the back of the auditorium. "People were crawling on each other, trampling each other."