Ninth in a series.

While the National Instant Criminal Background Check System remains the only square inch of compromise between the nation's divided gun camps, the costly federal program is failing to keep guns away from the dangerously mentally ill.

The White House describes the background check system, also known as NICS, as its "most important tool" to stopping gun crime. But more than a decade of data from the FBI and public health research reveals broad failings of the system, which has cost at least $650 million to maintain, a News21 investigation found.

Nearly all sides of the gun debate have devoted resources to strengthening the background check system, confronting technology gaps, coordination failures and privacy concerns.

Thirty states have passed laws mandating mental health reporting to NICS, four of them added in the last six months. Yet no organization has been able to address the larger concern - that NICS is poorly designed to identify those in society most likely to be violent.

"It's really casting a very wide net to try to find a few people, which is largely an impossible task," said Michael Norko, head of forensics at the Connecticut Department of Mental Health and Addiction Services. "It's not really a good public health measure. We really need to find a better way of doing this."

Federally licensed gun dealers are required to conduct a background check, either online or by phone, before each firearms sale. Within about 30 seconds, the system searches for prior criminal convictions, and in 38 states a history of severe mental illness as judged by a court.

But states are not required under federal law to submit mental health records to NICS. There are no consequences, financial or otherwise, if states choose not to send records, resulting in a national record-keeping system that is riddled with information gaps.

Millions of people who have been forced into hospitals for mental health issues are left out of the system. Only about 30 percent of the 4.4 million estimated mental health records in the United States over the last two decades can be found in NICS, according to research compiled in 2012 by the National Consortium for Justice Information and Statistics and the National Center for State Courts.

Those whose names are found in the system are unlikely to try to buy a gun. Out of all gun purchases blocked by the FBI over the last 16 years, fewer than 2 percent were because of mental health status. That amounts to 14,613 blocked sales since 1998.

The files are costly to locate and store, according to interviews with officials from 10 different states. Mental health records can be kept in courthouses, private hospitals, and state health facilities across each state. There were 2,083 agencies responsible for providing information for background checks across the country in 2010, including courts, state health departments, and psychiatric hospitals, according to the most recent Bureau of Justice Statistics report.

The system is also vastly overinclusive, six public health experts said in interviews.

The names of people who are kept in the database is based on a decades-old definition of "mentally defective," which relies on court decisions rather than doctors' orders. Under federal law, individuals with histories of violent psychotic episodes can legally buy guns as long as they never set foot in a courtroom.

Every one of the country's mass shooters since January 2009 could have slipped through NICS, according to a July 2014 study by the gun control organization Everytown for Gun Safety.

In 12 out of the 110 incidents identified by Everytown, the shooters had demonstrated some evidence of a mental illness, but there was no evidence that any of them had been mentally adjudicated or involuntarily committed for treatment.

Research over the last decade shows that it's nearly impossible to predict which individuals will commit gun violence, let alone find them through NICS.

"The ability of mental health professionals to pick out who's going to be violent, it's not much better than a coin toss. It's a needle in a haystack," said Jeffrey Swanson, a medical sociologist from Duke University who studies the intersection of guns and mental illness. "To focus only on mental health is misguided."

In addition to the FBI's annual budget for NICS, the Department of Justice has also handed out $56 million in state grants over the last five years to improve mental health reporting.

Despite years of investments, some states continue to struggle to submit records. Massachusetts has received $2,323,737 and collected just one record; Idaho has received $4,359,500 and collected 4,002 records; North Dakota has received $297,267 and collected 18 records; Oregon has received $4,542,109 and collected 30,059 records.

Thirty states have passed laws that require agencies to report mental health records, with the number of records tripling since 2011. But states continue to report difficulties with interagency coordination, technological abilities, and privacy laws.

Most state officials pointed to privacy concerns, outdated computer systems, and a potential chilling effect of more reporting meaning fewer seeking mental health treatment.

Federal government officials - along with lobbyists from Everytown for Gun Safety and the gun industry association National Shooting Sports Foundation - continue to push for more records. In 2015, the government will hand out $58 million in NICS mental health grants, its largest-ever pool of funding.

U.S. Rep. Andy Harris (R., Md.), who sits on the Appropriations Committee, said he does not support increased funding for NICS.

"Throwing money at the problem hasn't solved the problem in Maryland now for a decade and it won't solve the problem now," Harris said. "It's become clearer and clearer that we have difficulty restricting people with serious mental illness from acquiring a firearm. We need to think of another way."

Out of 23,292 individuals diagnosed with severe mental illnesses or committed to a mental institution, federal law would have disqualified only 7 percent from purchasing a gun, the study found. The majority of those studied never committed a crime, and most of those who did already had criminal records.

The final report concludes that the laws had a minimal impact on reducing gun violence.

"Background checks to enforce the federal mental health prohibitions - even if they are completely effective - will have a very small impact on overall crime in persons with serious mental illness," according to the report. "Most of those at risk are unaffected by the law."

During one of Ben Hundtoft's last hospital visits, his sister Marjorie remembers warning the emergency room doctor that he wasn't safe to be released.

"The doctor looked right at me and said, 'It's not against the law to be insane,' " said Marjorie Hundtoft, who lives in Portland, Ore.

Weeks later, on Jan. 1, 2012, her 32-year-old brother rented a hotel room and killed himself using a gun he had bought in a nearby shop. Despite more than five years of hospitalizations for psychotic episodes related to his bipolar disorder, Ben Hundtoft was able to purchase the gun legally.

Two years later, Marjorie Hundtoft said she wishes her family had been able to help, but it faced limited options.

"If my brother didn't want to see a psychiatrist, then he wouldn't go. We'd set up appointments, but he wouldn't go," she said. "At a minimum, I thought he needed some kind of outpatient treatment. They didn't offer that. There's really not much you can do."

Though he had once attacked his sister and threatened an ex-girlfriend, neither woman had wanted to send him to jail so he never acquired a criminal record.

Norko, the Connecticut forensics official who also worked 15 years in the state's maximum-security psychiatric hospital, said he believes the best approach to preventing firearms-related deaths is giving police the authority to temporarily confiscate weapons in dangerous situations.

Norko is now leading a study on guns that have been seized by police in Connecticut, one of just two states that allow the practice. Most of the 800 cases he's studied involve "regular folks" whose relatives or friends call the police because the person is "sitting there with a gun in their lap and an empty bottle of Jack Daniel's," Norko said.

Gun suicides outnumbered gun homicides nationally by about a 2-1 ratio in 2012, a News21 investigation found.

Some states have attempted to better identify dangerous individuals before they harm others. California and New York have recently passed controversial legislation that requires doctors and other health-care professionals to report people who present credible threats to themselves or police.

New Jersey is considering mandating mental health screenings for anyone looking to purchase a firearm, while states like Nevada have turned to similar types of screenings in schools to identify people with potentially dangerous mental illnesses.

TOMORROW: States challenge federal gun laws.