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Illinois lawmakers moved swiftly after last year's massacre at Virginia Tech to make it harder for anyone with a history of mental illness to buy guns, fortifying what were already some of the nation's toughest weapons laws.

But the new measure does not take effect until June. And whether it would have prevented last week's bloodbath at Northern Illinois University is far from clear.

Steven Kazmierczak, the 27-year-old grad student who bought an arsenal of guns in recent months and used them to kill five people and commit suicide, had been on medication and was said to have spent time in a psychiatric center as a teen in the late 1990s.

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But state Sen. Dan Kotowski, a sponsor of the law that will require more detailed reporting to state officials about those who have received mental health treatment, said the sketchy information about Kazmierczak's medical history makes it impossible to know if he would have fallen under the law.

"This law is more comprehensive than most," the Democrat said Monday. "But everything needs to be evaluated and reviewed to address the problem so that something like this never happens again. This is the promise we have to make."

The measure, when it takes effect, will require health professionals to inform state authorities about patients who display violent, suicidal or threatening behavior. Right now, such information is reported to state officials only on people who have been institutionalized, not on those who receive only outpatient treatment.

Illinois adopted the law last June, and the governor signed it in August.

Virginia lawmakers, meanwhile, still are considering a package of bills to reform that state's mental health system in the wake of the Virginia Tech tragedy, including one that would make it easier to have people involuntarily committed.

The proposals are attempts to reform a mental health system that came under increased scrutiny since a mentally disturbed student, Seung-Hui Cho, killed 32 people and himself at Virginia Tech in April.

Unlike Cho, Kazmierczak showed few outward signs of trouble. He passed repeated criminal background checks and had a state firearm owner's identification card, which requires applicants to answer a series questions, including whether they have been in a mental hospital in the preceding five years. Authorities say they verify what the applicants put down.

A former employee at a Chicago psychiatric treatment center said last week that Kazmierczak was placed there after high school by his parents. She said he used to cut himself and had resisted taking medications. And Kazmierczak's girlfriend, Jessica Baty, told CNN on Sunday that he had been on an antidepressant but had stopped taking it about three weeks ago because "it made him feel like a zombie."

But even under Illinois' new law, it's not clear whether Kazmierczak said or did anything that would have triggered the reporting requirement and made him ineligible to buy guns.

Some argue the more stringent reporting rules could make it even harder to identify people who might be about to snap.

Gary Slutkin of the Chicago Project for Violence Prevention at the University of Illinois said the rules could have the unintended consequences of discouraging people from seeking help out of fear of being reported. He said that might be especially likely to happen in the case of someone fantasizing about going on a killing spree.

"If you have these ideas, you might be less likely to get help because you know for sure you'll be reported," he said.

Pro-gun forces also expressed skepticism such laws would have done any good in stopping someone like Kazmierczak.

John Boch, like many other gun-rights activists in Illinois, said the answer is for the state to loosen its gun laws, not tighten them, so that students could have been able to shoot back during the NIU attack. Illinois is one of only two states with an outright ban on carrying concealed weapons. Wisconsin is the other.

"This guy at NIU committed murder, for god's sake," Boch said. "What are a few more gun laws going to do to protect human life? There are a lot of laws he violated in killing those kids, but one more law won't make a difference to guys like that."