Authorities say Loughner used that same semiautomatic on Saturday in a Tucson shooting spree that killed six and injured 14, including Arizona Rep. Gabrielle Giffords. 

The apparent ease with which Loughner bought a gun, and the crime's eerie parallel to the 2007 Virginia Tech shooting, is sparking discussions about funding for mental illness and legislation related to gun laws for the mentally ill. 

Right now, according to the Federal Gun Control Act of 1968, anyone in the United States can buy a gun, provided they aren't a felon, an illegal alien or considered a danger to themselves or someone else. 

Loughner was none of those things. Criminal charges against him were dismissed and he has never been diagnosed with a mental illness.  Pima Community College officials have not said if they shared their request that Loughner submit to a mental health evaluation with anyone besides Loughner's parents.

"Here is a guy who couldn't enlist in the military and was kicked out of school," said Daniel Vice, a senior attorney with the Brady Center to Prevent Gun Violence. "Anyone would tell you, 'Don't give this guy a gun.'" 

The American Psychological Association says that mental illness and violence are rarely linked: they say the vast majority of people with mental illness are not violent, and the majority of violent acts are conducted by persons who are not mentally ill. 

Even so, talks have begun about increasing mental health funding and tightening gun laws to prevent the mentally ill from obtaining them. 

"We've frankly allowed our public mental health system to weaken," said Sen. Sherrod Brown (D-Ohio) on the "Rachel Maddow Show" Monday. "...We've got to find a way to rebuild that social safety net for people with a mental illness."

Rep. Grace Napolitano (D-Calif.), who co-chairs the Congressional Mental Health Caucus with Rep. Tim Murphy (R-Penn.), has said that mental health cuts at the state level were unlikely to be reversed, but that the shooting could spark new debate on the issue. Napolitano plans to reintroduce the Mental Health in Schools Act, which would increase funding for on-site school therapists.

Currently, schools can only recommend that a student get a psychiatric evaluation, as Pima Community College did for Loughner. 

After multiple run-ins with campus police, Loughner and his parents met with administrators on Oct. 4 and he dropped out of school. Three days later, the college sent him a letter telling him that before he could return to school, he had to "obtain a mental health clearance indicating, in the opinion of a mental health professional, his presence at the College [did] not present a danger to himself or others."

Mental illnesses like schizophrenia typically develop between the ages of 17 and 26 — college age. Mark Gale, the second vice president of the National Alliance on Mental Illness's California chapter, said NAMI won't take a stance on political issues like gun control, but that it's painfully clear the secondary education system needs to strengthen how it cares for students who may or do have mental illnesses. 

"Why didn't somebody get alerted so the system could have reached out to this young man?" Gale said. "Why didn't the phone call get made?" 

A similar situation unfolded in 2007 when Virginia Tech student Seung Hui Cho shot and killed 32 students on campus. Before the shooting, Cho had threatened to kill himself, and underwent a mental health assessment. Those evaluations produced two very different results: a psychiatric treatment facility decided he was not a danger to himself or others, but a special judge did, and required him to attend outpatient treatment. Cho didn't go. 

The federal gun law doesn't require states to report information about mental health, but Virginia is one of the 22 that does. A report from the Virginia Tech Review Panel found that Cho's case slipped by officials, who thought only those receiving in-patient treatment faced restrictions.

"Nationwide, the mental health care system is broken," said NAMI Executive Director Michael J. Fitzpatrick in a statement. "Arizona, like other states, has deeply cut mental health services. Arizona has a broad civil commitment law to require treatment if it is needed; however, the law cannot work if an evaluation is never conducted or mental health services are not available."

Reach Laura J. Nelson here, or follow her on Twitter: @laura_ nelson.