San Bernardino shooting: what we know

The FBI is investigating the San Bernardino, California, mass shooting that killed at least 14 people and wounded at least 21 more as a potential act of terrorism, the agency announced on Friday.

A couple was allegedly involved in the shooting, San Bernardino Police Chief Jarrod Burguan said at a press conference. They were killed during a shootout with police after a manhunt.

Burguan identified two suspects as Syed Farook, 28, and Tashfeen Malik, 27, who were married. Farook was reportedly an employee of the San Bernardino County Department of Public Health, which rented a conference room at the social services center in which the shooting took place on Wednesday.

Anonymous law enforcement officials told the New York Times and the Associated Press that the woman involved in the shooting pledged allegiance to ISIS, the jihadist organization, in a now-deleted Facebook posting. But there's no evidence that the group directed the couple to carry out the shooting. The group is instead believed to have acted as inspiration, if anything. "At this point we believe they were more self-radicalized and inspired by the group than actually told to do the shooting," one of the officials told the Times.

But since these reports come from anonymous sources, some caution is necessary — the investigation is early, and the story could change with further findings. The FBI did say, however, that at least one of the suspects had potential connections to terrorism.

The shooting is a devastating tragedy, but unfortunately one Americans are increasingly familiar with. And as more and more of these events end up in the news on what feels like a weekly basis, the country is being forced to consider why the US, more than any other developed nation, suffers from such extraordinary levels of gun violence.

What we know about the shooting at the Inland Regional Center in San Bernardino, California

The shooting began around 11 am Pacific time, according to police. Over several minutes, Farook and Malik opened fire with assault rifles and handguns at the Inland Regional Center, where county health officials had rented space for a holiday party. At least 14 people were killed, and at least another 20 were wounded at the center — although those numbers are subject to change. The suspects then fled from the scene in a dark-colored SUV.

Around 3 pm Pacific time, just hours after the shooting at the center, police pursued a tip and reportedly spotted an SUV in the area that matched the description of the suspects' vehicle. A car chase ensued. At least 20 police officers and the suspects, who Burguan said were dressed in "assault-style clothing," then exchanged gunfire. One officer was wounded, and two suspects were killed.

The suspects also appeared to leave behind three explosive devices at the center, all of which were disposed of, Burguan said.

Marybeth Feild, president and CEO of the Inland Regional Center, which serves people with developmental disabilities, told the Associated Press that the initial shooting took place at a conference room at the center, which was rented out by the San Bernardino County Department of Public Health for a holiday gathering. And at least one of the suspects was an employee for the county health department.

What we know about the two suspects, Syed Farook and Tashfeen Malik

BBC report tonight: "Just another day in the United States of America..." pic.twitter.com/ikw41FLbgz

— Brian Stelter (@brianstelter) December 2, 2015

San Bernardino Police Chief Jarrod Burguan identified the two dead suspects as Syed Farook, a US-born 28-year-old, and Tashfeen Malik, a 27-year-old of unknown nationality and Farook's wife.

Police officials said Farook worked for the county for five years, most recently as an environmental inspector. There were reports, Burguan said, that there was some sort of dispute before Farook left his employer's holiday party, returned with Malik, and allegedly opened fire.

Despite reports of a dispute at the holiday party, investigators now appear to believe that the attack may have been an act of terrorism. Anonymous law enforcement officials told the New York Times and AP that the couple seemed to "self-radicalize," and that Malik pledged allegiance to ISIS in a now-deleted Facebook posting — although the jihadi group is not believed to have ordered the attack, instead acting as mere inspiration.

The FBI is now investigating the shooting as a potential act of terrorism, due to evidence of preplanning and possible ties to terrorism. Still, the agency cautioned that the direct connections are only investigation for now and unconfirmed.

Still, it's important to caution that even if the couple did pledge allegiance to ISIS, that does not mean that ISIS planned and led the attack. Vox's Zack Beauchamp explained:

This is an important distinction: There is a very big difference between random people choosing to take up the ISIS banner and ISIS having the organizational wherewithal to plan and execute attacks from its home base. Random individuals inspired by ISIS are, fundamentally, less scary than an ISIS that's centrally planning and launching attacks from a continent away. ISIS has a lot more money at its command, and far more experience, than individual attackers. That means it could pull off bigger attacks.

It certainly seems the couple was preparing for an attack: According to Burguan, police found 12 pipe bombs and more than 2,000 rounds of ammunition in the suspects' home.

The police chief said that the couple bought a pair of handguns on their own. But their two assault-style rifles, which are restricted in California, were purchased by someone who's currently under police investigation.

Co-workers told the Los Angeles Times that Farook recently traveled to Saudi Arabia and returned with a wife he reportedly met online. The couple had a baby and appeared to be "living the American dream," said Patrick Baccari, a health inspector with the county. (The couple reportedly left their 6-month-old daughter with their grandmother before they carried out the attack.)

Are mass shootings on the rise? It depends on which definition you use.

Mother Jones

With 14 people dead, the San Bernardino shooting would count as a mass shooting under any definition. But whether these types of shootings are more common today depends on which definition you use for mass shootings.

There's some debate about how to define mass shootings. But under one definition — shootings at a public place in which the shooter murdered four or more people, excluding domestic, gang, and drug violence — they appear to be getting more common, as the chart above from Mother Jones, based on an analysis from Harvard School of Public Health, shows.

But not everyone agrees with this definition. Northeastern University criminologist James Alan Fox, for example, defines mass shootings as any shooting in which at least four people were murdered. Under those terms, mass shootings don't appear to be increasing. Researchers from the Harvard School of Public Health call that definition too broad, since it includes domestic, gang, and drug-related shootings that may not be considered mass shootings in layman's terms.

Still, some definitions are even broader. Under the definition used by the Mass Shooting Tracker (and Vox's map), mass shootings are those in which four or more people are shot, not necessarily killed. The Mass Shooting Tracker's organizers explained their reasoning on their website: "For instance, in 2012 Travis Steed and others shot 18 people total. Miraculously, he only killed one. Under the incorrect definition of mass shooting, that event would not be considered a mass shooting! Arguing that 18 people shot during one event is not a mass shooting is absurd."

But this debate is extremely arbitrary. A shooting is a shooting. The debate over which definition to use misses the broader problem with gun violence in America: Compared with other developed countries, the US has extraordinary levels of gun violence.

America's levels of gun violence are unique in the developed world

Javier Zarracina/Vox

No other developed country in the world has anywhere near the same rate of gun violence as America. The US has nearly six times the gun homicide rate as Canada, more than seven times as Sweden, and nearly 16 times as Germany, according to UN data compiled by the Guardian. (These gun deaths are a big reason America has a much higher overall homicide rate, which includes non-gun deaths, than other developed nations.)

In fact, no other developed country comes close to the levels of gun violence that America has, as this chart from Tewksbury Lab shows:

Tewksbury Lab

The correlation this chart demonstrates — more guns mean more deaths — has been backed by a lot of research. Whether at the state or country level, reviews of the evidence by the Harvard School of Public Health's Injury Control Research Center have consistently found that places with more guns have more deaths after controlling for variables like socioeconomic factors and other crime. "Within the United States, a wide array of empirical evidence indicates that more guns in a community leads to more homicide," David Hemenway, the Injury Control Research Center's director, wrote in Private Guns, Public Health.

This is widely believed by experts to be the consequence of America's relaxed policy approach to and culture of guns: Making more guns more accessible means more guns, and more guns mean more gun deaths. Researchers have found this is true not just with gun homicides, but also with suicides, domestic violence, and even violence against police.

In response to the shooting on Wednesday, President Barack Obama told CBS News that Americans should not accept the regularity of this type of gun violence: "There are steps we can take to make Americans safer and that we should come together in a bipartisan basis at every level of government to make these rare as opposed to normal. We should never think that this is something that just happens in the ordinary course of events."

At the same time, other developed nations have had some big successes curtailing gun violence by reducing the number of guns. After a 1996 mass shooting in Port Arthur, Australia, killed 35 people and wounded 23 more, lawmakers passed new restrictions on guns and imposed a mandatory buyback program that essentially confiscated people's guns, seizing at least 650,000 firearms.

According to one review of the evidence by Harvard researchers. Australia's firearm homicide rate dropped by about 42 percent in the seven years after the law passed, and its firearm suicide rate fell by 57 percent. Although it's hard to gauge how much of this was driven by the buyback program, researchers argue it likely played some role: "First, the drop in firearm deaths was largest among the type of firearms most affected by the buyback. Second, firearm deaths in states with higher buyback rates per capita fell proportionately more than in states with lower buyback rates."

Still, similar measures would be very difficult to pass in America, a nation in which gun culture and ownership are tremendously ingrained. And gun owners are backed by a powerful lobby: the National Rifle Association. Combined, these forces have stopped any serious gun legislation from passing at the federal level — although some states have passed new restrictions in the past few years.

But given the research, America's policies and attitudes toward guns have clear, deadly costs — including, perhaps, more events like the San Bernardino shooting.

Watch: America's biggest gun problem is the one we don't talk about