Law enforcement sources confirm that Northern Illinois University shooter Stephen Kazmierczak struggled with persistent mental illness that, at times, had the potential to make him a danger to himself, but he was, nevertheless, able to legally purchase the guns he used in his campus rampage.
After the shootings, NIU parents expressed outrage and disbelief over his access to guns, echoing grievances brought up by parents after last April's shootings at Virginia Tech.
"Why was this tormented young man able to carry out this massacre?" NIU parent Connie Catellani asked. "How could he legally obtain a weapon, designed to kill so many people in such a short time?"
Law enforcement officials told ABC News that Kazmierczak's parents placed him in a Chicago mental institution, for months of intensive treatment, when he was a teenager, and that he remained on medication as an adult.
Despite past treatment for mental health problems, Kazmierczak, 27, was able to purchase four guns in three visits to a gun store in Champaign, Ill., over a six-month period. Each time, he filled out a federal form, which asks two critical questions:
"Have you ever been adjudicated mentally defective (which includes a determination by a court, board, commission or other lawful authority that you are a danger to yourself or to others, or are incompetent to manage your own affairs)?" the form asks, "or have you ever been committed to a mental institution?"
Federal law says that if a court orders a person's commitment to a mental institution, that information is supposed to go into a federal database. A background check against that database would flag such a gun buyer, who would not be legally allowed to buy a firearm.
Police believe Kazmierczak's parents — not a judge — voluntarily committed him. Under current law, that voluntary commitment by his family would not make it illegal for him to purchase guns.
Gun control advocates say the law presents a gaping, potentially dangerous loophole.
"Right now, the presumption in American society is that anybody should be able to get a gun at any time, very quickly. And we need to start saying that, for some people, who have shown clear signs of being mentally troubled, of being a danger to themself or others, that that should no longer be the presumption," said Paul Helmke, president of Brady Campaign to Prevent Gun Violence, told ABC News.
"Perhaps they can show that they are no longer a danger," he said, "but the presumption should be, no gun until you've had a clear showing that you're beyond that."
Ye even if Kazmierczak had lied on the form about his mental health, or if a judge had ruled him mentally incompetent or dangerous, authorities say it is unlikely a background check would have blocked the gun sales.
The reason: mental health records are not always readily available to police.
Seung-Hui Cho, the shooter in the Virginia Tech massacre, who killed 32 people before taking his own life, was able to buy a gun, even though a court had previously concluded that he was a danger to himself and others.