There's a troubling trend showing up in recent school shootings – the use of ghost guns.
These weapons, which are also known as “privately made firearms”, have been used in at least four school shootings since November.
The most recent was in near Kansas City this month.
Gun violence experts say ghost guns are easy to assemble and difficult to trace.
“When you talk about a traditionally manufacturing firearm, it's very difficult, if not impossible for those to be sold online. But since these are not considered firearms under federal law, when they don't have a serial number and they haven't reached a certain stage of manufacturing, they can be sold online, just like any other product,” said Alex McCourt, PhD at Johns Hopkins Center for Gun Violence Prevention and Policy
There's a lack of data around just how often ghost guns are being used in crimes.
Experts believe they are used more often than is reported.
Numbers provided by ATF show the number of privately made firearms recovered from crime scenes across the country has increased in recent years.
In 2016, there were about 1,700 suspected privately made firearms reported to ATF.
In 2020, that number increased to 8,700.
“We have these laws that that research has shown us can reduce gun violence. These include permit to purchase laws, other background check laws, certain domestic violence prohibitions. And if you can access these kits and these guns and even 3D printed guns and subvert those laws, then those laws lose some effectiveness, and I think that that could have serious implications for the country,” said McCourt.
Nine states currently have laws involving ghost guns.
A few cities also restrict them, including Denver.
But gun violence experts say without some kind of federal law, it may be difficult for states to have much of an impact.
A proposed rule the ATF is considering right now would regulate the online kits as guns.
That means they'd be required to have serial numbers and could only be sold, at least initially, by licensed manufacturers and dealers.