A shooting suspect is in custody after a reported shooting at Townville Elementary School in Anderson County, South Carolina, multiple local news outlets reported.

Here’s what we know:

At around 1:45 pm, Anderson County deputies were called to the school for a possible shooting. The shooting is believed to be over.

A teenage suspect is currently in custody, local officials said.

At least two children and one teacher were injured. Their injuries don't appear to be life-threatening, WYFF 4 reported.

There was a gun homicide near the school. Officials believe the victim was a parent of the shooting suspect, suggesting a possible connection.

The school evacuated children to a nearby church, where parents then picked them up.

Here’s what we don’t know:

Who the shooter was

The Townville Elementary School shooting is the 37th school shooting in 2016, based on Everytown for Gun Safety’s tracker.

The shooting is a devastating tragedy, but unfortunately one that Americans are increasingly familiar with. As more of these events end up in the news, the country is consistently forced to consider why the US, more than any other developed nation, suffers from such extraordinary levels of gun violence. And it seems easy access to firearms provide one answer.

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

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 of Canada, more than seven times Sweden's, and nearly 16 times Germany's, 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.)

What's more, there appears to be a correlation between America's high levels of gun violence and gun ownership, as this chart from Tewksbury Lab shows:

Research reviews by the Harvard School of Public Health's Injury Control Research Center have concluded that more gun ownership leads to more gun violence. Other factors, such as socioeconomic issues, contribute to violence, but guns are the one issue that makes America unique relative to other developed countries in comparable socioeconomic circumstances.

Studies have found this at both the state and country level. Take, for instance, this chart, from a 2007 study by Harvard researchers, showing the correlation between statewide firearm homicide victimization rates and household gun ownership after controlling for robbery rates:

A more recent study from 2013, led by a Boston University School of Public Health researcher, reached similar conclusions: After controlling for multiple variables, the study found that a 1 percent increase in gun ownership correlated with a roughly 0.9 percent rise in the firearm homicide rate at the state level.

This holds up around the world. As Vox's Zack Beauchamp explained, a breakthrough analysis in the 1990s by UC Berkeley's Franklin Zimring and Gordon Hawkins found that the US does not, contrary to the old conventional wisdom, have more crime in general than other Western industrial nations. Instead, the US appears to have more lethal violence — and that's driven in large part by the prevalence of guns.

"A series of specific comparisons of the death rates from property crime and assault in New York City and London show how enormous differences in death risk can be explained even while general patterns are similar," Zimring and Hawkins wrote. "A preference for crimes of personal force and the willingness and ability to use guns in robbery make similar levels of property crime 54 times as deadly in New York City as in London."

Guns are not the only factor that contribute to violence. (Other factors include, for example, concentrations of poverty, urbanization, and alcohol consumption.) But when researchers control for other confounding variables, they have found time and time again that America's high levels of gun ownership are a major reason the US is so much worse in terms of gun violence than its developed peers.

The research shows gun control policies can help

How can the country address this? The research shows tightening existing gun control measures in the US would help: Studies in both Connecticut and Missouri suggested that gun licensing laws in those states helped reduce homicides and suicides.

But as Harvard's David Hemenway told Vox's Dylan Matthews, it would likely take decades for the mild gun control measures proposed in the US to have a significant impact. "It's all speculation," Hemenway said. "I suspect it would take a while (decades) for the US to get down to gun violence levels of other developed countries because a) we have so many guns which are durable, and b) we have a gun culture — we tend to use guns more often in more situations than citizens of other developed countries."

To have a more immediate impact, then, the US would have to find a way to quickly remove the number of guns in circulation. Other countries have actually done that: In Australia, after a 1996 mass shooting, 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 policies would be difficult to pass in America, a nation in which gun culture and ownership are tremendously ingrained — notably, in the Second Amendment. 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 Townville Elementary School shooting.