What 130 of the worst shootings say about guns in America

John R. Houser was dangerously mentally ill, too ill to carry a gun. Of that, there is little doubt.

Over 16 years, Houser, 59, had been charged with hiring a man to burn down a lawyer's office and named in a domestic violence complaint. In 2008, after Houser threatened to kill his daughter's fiance, a judge issued a temporary restraining order and ordered him hospitalized for psychiatric evaluation. In 2014, he threatened to shoot law enforcement officers who were trying to evict him, then booby-trapped the house to start a natural gas fire.

His record was frightening enough that an Alabama sheriff refused to issue him a concealed-weapons permit. But like most states, Alabama requires no permit to buy a firearm. His wife said she repeatedly threw his handguns into the Chattahoochee River, fearing that he would harm himself or others. Houser just bought more.

Holed up in a Motel 6 in July 2015, Houser wrote in a journal that Dylann Roof, the white man charged with gunning down nine black members of a historic Charleston, South Carolina, church the previous month, had the right idea but the wrong targets.

"Thank you for the wake-up call, Dylann," he wrote.

Later that month, Houser walked into a movie theater in Lafayette, Louisiana, carrying a .40-caliber semi-automatic pistol he had bought at a Phenix City, Alabama, pawnshop the year before. Ten minutes into a showing of the comedy "Trainwreck," he opened fire, killing two moviegoers and wounding nine more. Then he put the gun in his mouth and pulled the trigger.

After nearly two decades of expanding legal access to firearms, a succession of horrific shootings like Houser's have refocused attention on gun control. Since the 2012 massacre of 26 elementary schoolchildren and adults in Newtown, Connecticut, gun control advocates have scored some significant victories in state legislatures. Nationwide, several polls suggest that public opinion has shifted markedly in favor of stricter gun laws.

And for the first time since Al Gore called for tighter firearm restrictions in his losing 2000 campaign, gun control is a top-level issue in the presidential contest, as well as in two close Senate races and four state ballot initiatives.

"The national dialogue has changed," said professor Robert J. Spitzer of the State University of New York at Cortland, who has written five books on gun policy.

Still, an examination of high-casualty shootings emphasizes not only how porous existing firearms regulations are but also how difficult tightening them in a meaningful way may be.

The New York Times examined all 130 shootings last year in which four or more people were shot, at least one fatally, and investigators identified at least one attacker. The cases range from drug-related shootouts to domestic killings that wiped out entire families to chance encounters that took harrowing wrong turns.

They afford a panoramic view of some of the gun control debate's fundamental issues: whether background checks and curbs on assault weapons limit violence; whether the proliferation of open-carry practices and rules allowing guns on college campuses is a spark to violence; whether it is too easy for dangerously mentally ill or violent people to get guns.

The findings are dispiriting to anyone hoping for simple legislative fixes to gun violence. In more than half the 130 cases, at least one assailant was already barred by federal law from having a weapon, usually because of a felony conviction, but nonetheless acquired a gun. Including those who lacked the required state or local permits, 64 percent of the shootings involved at least one attacker who violated an existing gun law.

Of the remaining assailants, 40 percent had never had a serious run-in with the law and probably could have bought a gun even in states with the strictest firearm controls. Typically those were men who killed their families and then themselves.

Only 14 shootings involved assault rifles, illustrating their outsize role in the gun debate. Nearly every other assailant used a handgun. That is in line with a federal study that concluded that reviving a 1994 ban on assault weapons and ammunition feeding devices that hold more than 10 rounds would have a minimal impact, at best, on gun violence.

But there were also cases in which victims arguably would have lived had they been in a state with tighter firearms restrictions, because it would have been harder for their attackers either to get guns or to carry them in those circumstances. That includes several of nine attackers who were dangerously mentally ill but still met the federal standard for gun possession.

For instance, Houser's two forced hospitalizations for mental illness — lasting from one week to almost a month — did not disqualify him from buying a gun under federal or Alabama law because no court had involuntarily committed him for treatment. Yet in at least six states, his history of illness and violence would probably have barred him from possessing a gun or made it extremely hard to obtain a permit to buy one.

Heath Taylor is the sheriff in Russell County, Alabama, where Houser lived and legally bought the handgun used in his assault. He said Houser should have been barred from gun ownership years before he opened fire in the Louisiana theater.

"The country has to address this," Taylor said. "I'm not for labeling someone as mentally ill for the rest of their lives, but there are warning signs that should prevent the purchase of a gun, and we are just not doing it."

Do background checks work? The majority of assailants would have failed but got guns anyway.

In two earlier articles, The Times analyzed the 358 shootings last year — almost one a day — in which at least four people, including attackers, were killed or wounded.

For this article, focusing only on the fatal shootings in which at least one attacker was identified, we sought to determine whether those assailants legally possessed their weapons, what type of gun was used and whether tighter gun laws might have averted their assaults.

The fact that so many cases involved attackers already barred from owning guns goes to a central issue in the gun control debate: whether background checks by licensed dealers should be expanded to include gun shows and private sellers.

To the National Rifle Association and other gun rights advocates, such statistics show that the current system has failed to keep guns out of criminals' hands and should be fixed, not expanded.

Donald Trump, whose Republican presidential candidacy draws deep support from the NRA, has cited federal studies of state prison inmates showing that more than 3 out of 4 got their guns from friends or relatives or on the street, avoiding the licensed dealers who would check their backgrounds. During the presidential debates, Trump argued that tougher police tactics, not tighter firearms laws, were the remedy for gun violence.

Hillary Clinton has noted that since 1994, when licensed dealers were first required to check potential buyers, about 2.6 million sales have been blocked to people barred from gun ownership. Expanding background checks, she says, will close a vast loophole in an otherwise effective law.

"We've got to get guns out of the hands of people who should not have them," she said during the first debate.

Polls indicate that the vast majority of Americans, including gun owners and NRA members, support that approach. The debate is white hot in Maine and Nevada, where voters will decide next month whether to join 18 states and the District of Columbia that already require some form of broader checks.

It was virtually impossible to determine whether expanded background checks would have deterred the illegally armed attackers involved in the shootings examined for this article. In many cases, police officers never recovered the weapons, and even when they did, they did not always investigate where the firearms came from. A trace by the federal Bureau of Alcohol, Tobacco, Firearms and Explosives generally shows only the original seller and buyer, while the typical gun used in a crime is 11 years old.

But a stronger law could arguably have made it harder for at least one gunman to find a willing seller. David Ray Conley III, 48, had already spent nearly 12 years in prison for five felonies, including armed robbery, when he bought a handgun online in the summer of 2015, according to broadcast reports.

A few weeks later, law enforcement officials told reporters then, Conley climbed through the unlocked window of his ex-girlfriend's house in Houston and shot her, her husband and her six children, ages 6 to 13, including his own son.

A judge has imposed a rule of silence in the case, cloaking details of Conley's gun purchase. He has pleaded not guilty.

Jennifer Baker, a spokeswoman for the NRA's Institute for Legislative Action, called Conley's reported online firearm purchase an anomaly. "One case," she said. "One case out of how many?"

But to gun control advocates, the example bolsters studies indicating that criminals are flocking to online gun bazaars where individual, unlicensed sellers need not check the backgrounds of in-state buyers. In Nevada, a study by Everytown for Gun Safety, a gun control group founded by former Mayor Michael Bloomberg of New York, found that nearly 1 in 11 shoppers on such sites was legally prohibited from possessing firearms.

Denying guns to the dangerously mentally ill: Is the bar set too high?

Although mental illness is not a good predictor of violence, many gun policy experts agree that federal law allows too many people who are dangerously unstable to buy firearms virtually without oversight. It denies guns only to people who have been involuntarily committed for inpatient treatment, a practice vastly more complicated and far less common than in 1968, when the federal law was adopted.

A handful of states have adopted tighter restrictions, limiting gun ownership by mentally ill people who have been voluntarily admitted for inpatient care, forced into outpatient treatment or held for as little as 72 hours. A few, including New York, require mental health professionals to report people who appear dangerous to themselves or others — information that can be used to deny them a gun purchase.

And in Washington state, a ballot measure, modeled after a California law, would allow law enforcement officers, family and household members to seek emergency court orders disarming people at risk of harming themselves or others. Three other states have similar but more limited measures.

Joshua Horwitz, executive director of the Coalition to Stop Gun Violence, said two decades of experience with restraining orders against domestic abusers had proved that such court interventions reduce violence. The NRA disagrees, saying the Washington measure would strip gun owners of their rights "merely on the say-so of someone else."

No such provisions were in place in the states where mentally ill gunmen carried out nine of the 130 shootings last year. Police inquiries into several cases later showed that family and household members feared disaster in the making but felt helpless to avert it.

In Menasha, Wisconsin, Sergio Valencia del Toro, a 27-year-old Air Force veteran who had served in Iraq, had quit taking psychiatric drugs or seeking psychological help after 14 visits in four years to military or veterans' health clinics.

He battled alcoholism, saw visions out of the corner of his eye, imagined himself spraying bullets into a packed dining room and once held a gun to his head on an outing with his girlfriend's family. He told a mental health worker that he contemplated suicide daily. According to a police report, Charles Peterson, his girlfriend's father, said he had ordered del Toro to remove his firearms from their home, although he denied that in a brief phone interview with The Times, saying, "There were no reasons to take guns from him."

Del Toro's girlfriend, Haylie Peterson, said he told her he wanted to rejoin the military "so that he could kill people." Fearing he was a sociopath, she was on the verge of ending their relationship. Yet she did not report his violent tendencies to the authorities because "she felt it would not have done any good," a police report stated.

Neither did del Toro's psychologist at the Department of Veterans Affairs, even after reviewing a November 2014 disability questionnaire in which del Toro wrote that he had previously thought, "If I'm gonna take myself out, I might as well take other people with me." He wrote that he no longer felt that way, and the psychologist, noting that del Toro seemed to be functioning well, decided that he was not disabled.

Unaware of del Toro's psychiatric problems, the Menasha police hired him as an auxiliary officer in January 2015.

On a balmy Sunday evening four months later, news spread of a shooting on the town's popular pedestrian bridge. Immediately suspecting her boyfriend, Haylie Peterson checked the bedroom where he kept three rifles, three shotguns and four handguns, mostly bought online. Two pistols were missing.

Drunk and distraught, del Toro had bicycled to the bridge, where a family of five was walking their dog and watching the ducks. He gunned down an 11-year-old girl, her father and another man, wounding the girl's mother, before he shot himself.

When investigators obtained del Toro's health records, said Aaron Zemlock, a police spokesman, "We were kind of dumbfounded."

"I've been a gun owner my whole life," said Zemlock, who recently left the department, "but this guy was a ticking time bomb."

In Conyers, Georgia, relatives feared the same about Jeffrey Scott Pitts. Thirty-six and unemployed, he was schizophrenic but refused to take his medication, his cousin told law enforcement officers.

After Pitts barricaded himself in a room, his father obtained a court order to have him picked up by the police. He spent more than a month in a mental institution, although court records suggest that he was never involuntarily committed.

He was hospitalized again in 2011 "because he was so crazy" but was released the next day, his father, Miles Alan Pitts, told investigators.

"I knew something was going to happen," he said. "I figured he would either kill himself or kill us."

In five states and the District of Columbia, that first hospital stay would have meant at least a temporary ban on firearm purchases. But like most states, Georgia follows the looser federal standard.

When Jeffrey Pitts bought AK-47 and AR-15 assault rifles, his father locked them away in a basement safe. But unknown to him, Jeffrey had also bought a Glock .45-caliber handgun.

On a Sunday afternoon, exactly four weeks after the Wisconsin bridge shooting, he burst into a liquor store with his handgun, furious because the store owner had accused him of stealing. In less than six seconds, he fatally shot the owner and a customer.

He might have killed others had Todd Scott, a customer buying a six-pack, not fired at him with his own handgun.

"He was very surprised that he was not the only one in the store with a gun. He got the heck out," Scott said. It was one of only two of the 130 shootings last year in which law enforcement officials said a legally armed victim or bystander had fired back in a clear-cut case of self-defense.

Pitts then drove to his parents' house, where he wounded both of his parents before forcing his father to open the safe with the assault rifles. When Brad Lockridge, a deputy sheriff, confronted him in the garage, he was dressed in a bulletproof vest, holding the AR-15, loaded with a 100-round magazine. He fired at the deputy, who wounded him with a volley of bullets. Then Pitts killed himself with his handgun.

"Should he have had guns? No, that's why his parents took the guns from him," said Lockridge, now a city police officer.

"But legally was he able to purchase guns? Unfortunately, yes."

Research shows requiring a permit to buy a handgun helps keep guns out of dangerous hands.

Eleven states and the District of Columbia require a permit or license before purchasing a handgun or, in some cases, any kind of firearm. Most of them — and some other states, too — have broadened the federal ban on gun purchases to cover other high-risk individuals, including those convicted of serious, violent misdemeanors or drug, alcohol or firearm-related offenses, or anyone under 21. Massachusetts, New York and New Jersey also let law enforcement officials deny permits if an applicant appears to present a public safety risk.

Ohio is not in that group. So it was not hard for Barry Kirk to get a gun.

Kirk, a part-time Columbus, Ohio, ironworker, had a host of problems and a hair-trigger temper. In 2004, his wife accused him of punching her in the face, a criminal complaint that was dismissed after he underwent counseling. Five years later, when an aide in the governor's office said he could not help him get unemployment compensation, Kirk exploded again.

"I guess I'm going to have to make a big boom or start shooting people," he told the aide in a telephone exchange, adding, "I just want you to know this so when it happens and hits the newspapers, you'll know it was me."

Soon four police officers were at his door. "I asked Mr. Kirk if he planned to shoot anyone. Without hesitation, he stated, 'Yes,'" one officer wrote in his report. "Mr. Kirk stated if he ended up losing his house, he would carry out a shooting."

Kirk was arrested and pleaded guilty to telecommunications harassment, a serious but not violent misdemeanor in Ohio.

By 2015, his troubles had deepened. His wife had left him. A bank was foreclosing on his house. He had filed for bankruptcy.

Across the street, the Anderson family presented a stark contrast. John Anderson, 31, had started an asphalt paving company. His wife, Christina, 30, was studying to be an X-ray technician. They often hosted neighborhood barbecues. "Everyone liked them," said Gregory Sheppard, a Columbus police detective.

Kirk was the exception. Anderson had briefly employed him but dismissed him, suspecting illegal drug use, said Tina Chaffin, Anderson's mother-in-law.

On the Saturday before Thanksgiving, after passing a background check, Kirk, 50, bought a Glock semi-automatic handgun from a Field and Stream sporting goods store. That Monday, as Anderson carried groceries into his kitchen after work, Kirk burst through the back door, demanding money, then killed Anderson with two bullets to the head.

Seven-year-old Landon Anderson fled upstairs to his sister's bedroom. His mother ran after him, locked the door and frantically called 911.

In a scene befitting a horror movie, Kirk blew out the lock and killed the mother and son. The daughter, Makyleigh, then 12, was shot in the shoulder and both hands, which she had thrown up in protection. A third bullet grazed her skull. Sheppard said she survived only because Kirk "assumed she was dead."

Police officers killed Kirk as he fled.

Like roughly one-third of Americans, Anderson kept a handgun at home, for protection. But like an estimated 99 percent of crime victims, he did not use it — probably because he had no chance to retrieve it, the detective said. Chaffin, who is now raising Makyleigh, said Kirk did not deserve the same gun rights as her son-in-law.

"I don't understand how some of these people get to even purchase a gun," she said.

Daniel Webster, director of the Johns Hopkins Center for Gun Policy and Research, said requiring a permit to buy a handgun is perhaps the most effective way to keep firearms away from dangerous people. In the three years after Missouri eliminated its requirement in 2007, his research found, gun homicide rates jumped 25 percent, even as they declined nationwide. Conversely, Connecticut's gun homicide rate fell 40 percent in the decade after it began requiring permits in 1995.

"It is just a lot more intimidating to go eyeball-to-eyeball with law enforcement rather than just going into your local gun shop to buy a gun," Webster said.

William B. Evans, Boston's police commissioner, said Kirk would not have passed muster with his department. "When in doubt, I put the safety of the public first," he said.

By openly displaying guns, some rights advocates push the envelope on what is considered acceptable.

Although Americans broadly support some restrictions, like broader background checks, the ideological and cultural divides on others are yawning. Perhaps the best example is the debate over "open carry" — the right to display firearms, Old West-style, in public.

Few states restrict individuals from openly carrying loaded firearms in public, although many prohibit it in specific locations such as schools, according to the Law Center to Prevent Gun Violence. Until recently, however, few gun owners in cities tested that latitude. Even the NRA warned its Texas members in 2014 that carrying rifles into restaurants and coffee shops "can be downright scary" and might provoke a backlash — before quickly disavowing the statement.

Increasingly, though, some gun owners are showing up visibly armed in crowded settings like political rallies as an expression of expansive Second Amendment rights, arguing that they are deterring criminals and trying to make openly carrying firearms seem an everyday, accepted practice.

To some city police chiefs, like Edward A. Flynn of Milwaukee, that is "lunacy." "It puts everyone at risk." he said. "Everyone."

Clinton has argued that cities and rural areas should be allowed to adopt different gun rules. But over the years, gun rights groups have persuaded the vast majority of states to strictly limit the power of local governments to regulate guns, according to the law center.

The open-carry trend is new enough that researchers have yet to assess its effect on public safety. But after a sniper killed five police officers in Dallas in July, President Barack Obama, the city's mayor and the police chief all said the police had struggled to distinguish the gunman from law-abiding citizens with rifles slung over their backs.

And in Colorado Springs last year, open-carry laws contributed to an 11-minute delay in the police response to Noah Harpham, a mentally ill man on a killing spree.

Although Harpham, 33, had never threatened violence, he was bipolar, had quit taking medication and had not seen his psychiatrist for about two years. By last Halloween, he had become so irrational that his stepfather took a plane to Colorado Springs, planning to hospitalize him, against his will, if necessary.

But before his stepfather arrived, Harpham had left his apartment, carrying an AR-15 rifle and two small gas cans. A neighbor called 911, only to be told by the dispatcher that Colorado "is an open-carry state, so he can have a weapon and be walking around with it" although she did note that the gas cans seemed "pretty suspicious." The call was classified as not urgent, then upgraded to a possible burglary.

Eleven minutes later, the neighbor called back, weeping and asking for an ambulance. "I just called a few minutes ago and the guy came back out," she said. "He fired a gun at somebody, and he's laying on the street dead."

The dead man was Andrew Myers, 35, a father of two and an Army veteran who had survived three tours in Iraq. Riding past Harpham on his bicycle, he had shouted: "What are you doing? You can't be out here with an automatic weapon on the street." Harpham shot Myers in the head, chest and back. Minutes later, he killed two women smoking on a front porch.

By the time the police reached him, Harpham was walking backward down the roadway median, a half-mile from where he was first spotted. After he fired at the officers, they shot and killed him.

Colleges are the new gun rights frontier. Opponents call that foolish.

In 1981, Arizona was among 19 states that prohibited gun owners from carrying concealed handguns outside their homes, researchers say. Thirty-five years later — in a powerful testament to the gun rights movement's success — carrying a concealed weapon is legal nationwide; eight states, including Arizona, require no permit to do so.

One new frontier is the college campus, where firearms advocates have mounted a state-by-state campaign to allow guns. Opponents argue that giving guns to young people who are still learning to make responsible decisions — and are often soaked in alcohol, testosterone or both — is a recipe for disaster. But the movement has gained momentum. Texas last year became the eighth state to let students carry concealed weapons on campus.

Arizona has yet to adopt such a law, but firearms do have a foothold there: in 2009, the Legislature outlawed any restrictions on keeping guns in locked vehicles, as long as the firearms are out of sight. That overrode the state educational board's broad prohibition against firearms at public universities.

Steven Jones grew up shooting in pistol competitions, guided by his father, an NRA instructor who sold gun supplies, according to police records. As an 18-year-old freshman at Northern Arizona University in Flagstaff, he kept a .40-caliber Glock 22 handgun in the glove compartment of his red Mustang.

One Friday evening last October, Jones parked his car on campus while he socialized with friends from his new fraternity, Sigma Chi. One of them later told the police that they knocked on the door of an apartment building where members of a rival fraternity, Delta Chi, were partying and drinking heavily — a stunt called "ding, dong, ditch."

A half-dozen or more Delta Chi members ran out, yelling, and pursued them. One punched Jones in the face, knocking off his glasses. His two friends were knocked to the ground.

Jones ran to his car and unlocked it with a key fob. He told the police he was "freaking out" and could not find his keys to drive away, even though they were in his pants pocket. He retrieved his loaded gun, got out of the car, flipped on the weapon's attached light and pointed it at Delta Chi members.

"Don't move," he said he yelled, warning that he was armed.

Some witnesses said Colin Brough, a 20-year-old junior, took a step or two forward. Jones said two students charged at him, threatening to kill him. Without his glasses, he had trouble aiming, so he "hoped for the best," he said. He shot Brough just below the heart and in the shoulder. He hit a second student in the arm and hip.

The courtyard erupted into screams: "Why do you have a gun?" "Why did you shoot?" Several students tackled Jones and started punching him, trying to get the gun.

Afraid they would use it to kill him, Jones said, he fired into the air to drive them off. He hit a third student in the neck, just a fraction of an inch from a major vein, and a fourth student twice in the back, shattering his kidney.

As officers flooded the courtyard, Jones grew hysterical.

"I am so sorry," he cried. "I'm so scared. Can I call my mom?"

Brough, a gregarious business management major, died of internal bleeding in the courtyard.

"Where does the responsibility lie?" asked Kimberly Prato, whose son Nicholas was shot. "Do you blame it on an 18-year-old who was given a weapon by his parents to go to college? I don't know the answer, but I know it is out there."

Jones was indicted on charges of first-degree murder and aggravated assault. He has pleaded not guilty, claiming self-defense.

This year, a bill that would have allowed students and professors to carry concealed guns on campuses like Jones' died in a legislative committee. Similar bills were killed in 16 other states, according to the law center.

Douglas Brough, Colin's father, said he shudders to think what would have happened had other students been armed that night.

"Are you kidding me?" he said. "It would have been like the O.K. Corral."

Agustin Armendariz and Giovanni Russonello contributed reporting, and Susan C. Beachy contributed research.