Investigators say the black handgun allegedly recovered from Luigi Mangione, the suspect arrested in connection with the murder of a health care executive, appears to be a ghost gun — a firearm that can be assembled at home.
Officials said the device may have been manufactured using a 3D printer, but would need to be tested by ballistic missile experts to be sure.
The killing of UnitedHealthcare CEO Brian Thompson has once again shed light on this controversial gun, which advocacy groups have called “the fastest growing gun safety issue in the country.”
Here's what to know about these firearms.
What is a ghost gun?
They are called ghost guns because they are potentially untraceable. They can be assembled at home, either from scratch or through gun parts kits, and do not carry serial numbers.
The weapon Mr. Mangione allegedly carried in his backpack appeared to be a typical one. The arrest warrant described the gun as a “semi-automatic handgun with what appears to be a 3D printed receiver with a metal slide and a silencer.”
Police said they were able to fire 9mm rounds, consistent with the type of weapon used in the fatal shooting of Mr. Thompson in New York the previous week.
The Biden administration, which advocates for gun regulation, has previously described ghost weapons as “ridiculously easy” to collect.
Until August 2023, anyone with access to the Internet can legally purchase many of the parts needed to make a gun without a background check. Online tutorials explain how to put the pieces together into a fully functioning firearm in less than an hour.
How big a problem do they face?
Experts have called ghost weapons the nation's fastest-growing gun safety problem. They have been increasingly used in high-profile shootings.
According to figures from the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), 20,000 suspected ghost guns were reported recovered by law enforcement in criminal investigations in 2022 — a tenfold increase from 2016.
Authorities say that without serial numbers on their frames, it is nearly impossible to track down dealers who illegally sell these weapons to minors or people without licenses.
A former government official doubted whether people's minds would change after Mr Thompson's murder. Juliet Kaym told BBC Radio 4's Today programme: “Ghost guns are a new factor in a very complex and violent country.”
Kaim, a former assistant secretary of state for policy at the Department of Homeland Security, said America finds it “extremely difficult” to restrict the use of firearms.
More than 48,000 people were killed by firearms overall in the United States in 2022, according to the Centers for Disease Control and Prevention (CDC).
Are ghost guns regulated?
The murder has renewed scrutiny of ghost weapons — which the Biden government has tried to regulate by saying they should be treated the same way as commercially available firearms.
Manufacturers of ghost gun kits are now required to include serial numbers on their products, and to conduct background checks on buyers.
In October, the US Supreme Court expressed its willingness to uphold the law, which gun rights groups objected to, saying the authorities had overstepped the bounds of existing legislation.
A ruling upholding the ATF's new regulation would mark a change for this Supreme Court, which has a conservative supermajority that has been largely skeptical of gun regulations.
Regarding guns more broadly, US President-elect Donald Trump has presented himself as a strong defender of the Second Amendment, which grants the right to bear arms. Earlier this year, he told the National Rifle Association (NRA) that he was the group's best friend.