UPDATE April 3, 2009: As authorities work to secure the site of a deadly shooting rampage in Binghamton, New York that claimed the lives of more than a dozen people, questions concerning the tragic incident continue to mount. In the days to come, one question will be paramount: Why?
In 2007, following a number of unrelated shootings, ABC News investigated the possible causes of these tragedies. That report follows.
In past incidents -- including the Virginia Tech massacre in April and the Trolley Square Mall shooting in February -- the perpetrator was later described as a loner, an outcast.
"All have that same theme of alienation and isolation," said Beverly Hills-based forensic psychiatrist Dr. Carole Lieberman. "Many of these shooters have been picked on by their peers or felt 'out of the loop.'"
"I think much of this stems from how we've become a much more isolation-oriented society," said Carolyn Wolf, senior partner at Abrams, Fensterman, Fensterman, Eisman, Greenberg, Formato & Einiger, LLP -- a mental health law practice in New York. "With computers and all of the technology that we now have available, people are much more easily able to be isolated, and with isolation comes withdrawal -- withdrawal from friends and family, as well as withdrawal from the medical system."
But mental health experts say these tragedies have something else in common -- they all point to a mental health system that minimizes the chances that these outsiders can get access to proper psychological services, which would possibly stop the tragedies before they occur.
"The gamut of mental health services has been lacking severely across the country," Wolf said.
"There are many dollars that are allocated for physical services, but mental health has been significantly overlooked," she said. "What all of this highlights is a very significant need for increased funds to help people who suffer from mental illness."
And it's not just a funding problem, they say. The set of laws governing intervention for mental health concerns are a patchwork across the country. New York, Wolf notes, has a state law providing for mental health warrants in which people can go through the courts to have their loved ones ordered to mental health treatment if they fear that they could become dangerous.
In Florida, legislation known as the Baker Act allows judges, law enforcement officials or mental health professionals to order individuals to receive mental health care if they are determined to pose a danger to themselves or others.
But not all states have such laws. And even in these states, admitting an individual in a potentially dangerous state of mental health is no simple task.
"You always have to meet certain legal standards in order to admit someone for mental treatment," Wolf said. "A person has to be deemed dangerous to themselves or others before they will intervene."
The solution, Wolf said, appears to lie in a combination of improvements, both within and outside the system, from increased funding, to better legislation, to a better overall understanding among the public of mental health issues.
"People need to become more educated as to what some of the signs of illness are, as well as the options for treatment," she said.
With this in mind, let's take a closer look at the Westroads Mall shooting, as well as other high-profile cases of mass shooting in the past.
Dec. 5, 2007: The Westroads Mall Shooting
The first hint that something terrible was happening at an Omaha mall came in the form of a 911 call received at 3:42 p.m.
Shortly afterwards, nine people at the Westroads Mall were dead -- including 19-year-old gunman Robert A. Hawkins.
Hawkins had reportedly been fired from his job at a McDonald's in the previous week, and had recently broken up with his girlfriend. According to reports by The Associated Press, Hawkins left a note in the home of his adopted family before the shooting spree. In it, he said he was "sorry for everything" and would not be a burden on his family anymore.
He also wrote, "Now I'll be famous."
"Robert was a desperate young man, who felt unseen and unloved by his parents, his girlfriend, his boss and the rest of the world," Lieberman said. "The only way he knew to become 'somebody' that others paid attention to was by creating news of his wreaking violence.
"Since he felt he wouldn't become famous for positive contributions to society, he settled for infamy as a mass shooter. Because he felt powerless and weak, he wanted to go out as someone who could inflict mass hysteria, fear, injury and death."
Indeed, those who knew Hawkins say he was an "introverted, troubled young man."
Hawkins, from Bellevue, Neb., was kicked out by his family about a year ago. He moved in with a friend's family, and Debora Maruca-Kovac and her husband welcomed him into their home and tried to help the teen.
In a TV interview, Maruca-Kovac described Hawkins as "a troubled young man who was like a lost pound puppy that nobody wanted."
And Hawkins had also experienced run-ins with the law -- missed opportunities, Lieberman said, for the detection and proper treatment of his mental problems.
"One difference between Robert and Cho Seung Hui [the gunman at Virginia Tech] and the Columbine shooters is that he had been convicted for felonies and misdemeanors," she said. "While he had the attention of the court, he should have been ordered into psychiatric treatment, or even juvenile detention."
April 16, 2007: The Virginia Tech Massacre
In some cases, however, the mental problems displayed by a shooter are too vivid to ignore.
Such was the case with Virginia Tech student Cho, whose disturbing video he shot of himself before he went on a shooting rampage sweeps away any doubt about his disturbed state of his mind.
The video, which Cho mailed to NBC News in a two-hour hiatus during the horrific shooting spree, features a violent and disorganized diatribe which psychological experts say offers a glimpse into a mind twisted by psychosis and rage.
"It appears that this was not schizophrenia, but some form of severe mental illness accompanied by paranoid delusional thinking, as reflected in his rantings on the video about people with trust funds and cognac and vodka," Dr. Redford Williams told ABC News shortly after the incident. Williams is director of Duke University's Behavioral Medicine Research Center in Durham, N.C.
Dr. Kathyrn Moss, attending psychiatrist in the Personalities Disorders Clinic at NewYork-Presbyterian/Weill Cornell, agreed that a combination of mental distress and isolation likely led to Cho's behavior.
"This is a mix -- a constellation of factors that came together in a horrific way," Moss said. "It's not just one thing. It can't be."
But his grave isolation -- as well as spotty access to mental health services -- could have played an important role in the student's rampage, which left 32 people dead and another 25 injured.
Records show that there were several instances during which Cho could have received the mental health help he needed. The police brought Cho to a mental health center in December 2005, where social worker Kathy Godbey determined that he represented a danger to himself or others, and that he could be put in temporary custody.
After another evaluation, psychologist Roy Crouse concluded that Cho was "mentally ill but did not present an imminent danger to himself or others, and did not require involuntary hospitalization."
As a result, a court magistrate released Cho, ordering outpatient treatment and follow-up. It is not clear whether Cho was ever contacted or participated in such treatment.
Moreover, questions linger as to whether Cho's mental health records were allowed to be released to his parents before the shooting took place.
Feb. 12, 2007: The Trolley Square Mall Shooting
Much like the most recent rampage in Omaha, the February shooting that occurred in Salt Lake City, Utah, took place in a bustling mall.
The Trolley Square Mall tragedy was the first mass shooting at a mall in 2007. In total, nine people were shot -- five of them fatally.
And the profile of the killer bears some similarities to others who have committed these types of shootings. Sulejman Talovic was an outsider, 18-year-old Bosnian immigrant who lived with his mother in Salt Lake City.
According to local reports, Talovic had a history of minor run-ins with the law. He was also a high school dropout.
But despite his past problems, for most there was little warning that he would show up at the Trolley Square Mall on a busy evening and start shooting people.
Though no clear motive for the rampage was ever established, a local newspaper reported shortly after the incident that Talovic claimed to be involved with a local gang.
Marie Smith, 23, a manager at a Bath & Body Works in the mall, later told The Associated Press that she had seen the gunman raise his gun and fire at a young woman during the incident.
"His expression stayed totally calm," Smith told the AP. "He didn't seem upset, or like he was on a rampage."
Feb. 13, 2005: The Hudson Valley Mall Shooting
According to local reports, Robert Bonelli Jr., age 24 at the time, was a shy outsider who lived in constant fear of being picked on for his nearly 300-pound physique.
And after his shooting rampage at the Hudson Valley Mall in Kingston, N.Y., which left two people wounded, mental health experts believe that it was this insecurity and isolation that may have been a key part of what drove him to the act.
"It is that same theme of alienation and isolation," Lieberman said. "Many of these shooters have been picked on by their peers or felt out of the loop."
According to a report in the Poughkeepsie Journal, Bonelli walked into a Best Buy holding an AK-47 rifle replica loaded with 60 rounds of ammunition. He began firing randomly, and he didn't stop until he had expended all of his ammunition.
His family would later reveal that they believed Bonelli had a death wish -- and that he wanted the police to do the job.
''It drove him to have himself killed by law enforcement that wasn't there in time,'' his uncle, John Bonelli, told the Journal. ''Because if they were there in time, this kid would have been in a body bag.''
Bonelli pleaded guilty to committing the shooting on May 20, 2006, and he was subsequently sentenced to 32 years in prison.
April 20, 1999: The Columbine Massacre
The school shooting at Columbine High School took place at the hands of students Eric Harris and Dylan Klebold on April 20, 1999. Many have pointed to the tragedy as both a template and catalyst for future shootings.
Indeed, Cho referenced the killers in his chilling video. And Bonelli reportedly had a picture of the killers taped to one of his bedroom walls.
But the case also raised awareness among many parents that the social isolation and brooding rage that can lead to such an attack could develop at home -- and largely unnoticed.
"In this case, the shooters were living with their parents, but their parents didn't have a clue who they really were," Lieberman said, adding that the episode shattered the illusion of the safety and security of an upper-middle-class upbringing.
"What matters is the attention and the love that the child is getting from their parents," she said.
In total, the rampage by the two students claimed the lives of 12 students and a teacher. The attacks wounded 23 others, and both of the boys committed suicide following the incident.
Lieberman said that if there is any lesson to be learned from Columbine -- as well as other more recent tragedies -- it is that parents and others should be on alert for the signs of dangerous mental health conditions -- and intervene before it is too late.
"People should report their suspicions to family members, the police, doctors, teachers and others in authority," Lieberman said.
Information from The Associated Press was used in this report.