What is a ghost gun? Police link untraceable firearm to CEO murder suspect Luigi Mangione

When the NYPD caught up with the man accused of killing UnitedHealth CEO Brian Thompsonthey found him with multiple fake IDs and a 9mm “ghost gun,” according to authorities.

What is a ghost gun? Since the rise of 3D printers in the early 2010s, these untraceable firearms have become increasingly common in American criminal cases.

However, since these weapons do not have serial numbers, it is basically impossible to know how many have been sold, how many are in circulation, and how many have been used in crimes.

What gun was found on Luigi Mangione?

We don’t know much about the weapon that police believe may have been used to kill Brian Thompson outside his Manhattan hotel last Wednesday.

When police arrested 26-year-old Luigi Mangione, he was “in possession of a ghost gun that had the ability to fire a 9mm round and a silencer,” NYPD Chief of Detectives Joseph Kenny said at a news conference Monday.

Kenny added that the weapon “may have been made on a 3D printer”.

If true, it would be one of many. Last year, the US Department of Justice announced that requests from local police forces to find ghost guns used in crimes have increased by more than 1,000 percent since 2017, from 1,629 reports to a staggering 19,273.

How are spirits created?

A ghost gun is a domestic firearm that does not have a serial number, meaning it cannot be traced back to its original purchaser if it is used in a crime.

It has always been possible to make such guns, but 3D printing has made it easier than ever before, and blueprints for doing so are widely distributed online.

Until recently, because of unusual laws in US firearms laws, it was unclear whether these types of weapons could even be regulated.

Under the Gun Control Act of 1968, anyone who wants to manufacture a gun for sale or distribution must put a serial number on every gun they make. The Brady Act of 1993 added a requirement for background checks on potential gun buyers.

But traditionally, the requirements referred to the existence of a “frame or receiver” – ie. the entire gun chassis into which all the other components were integrated – what made the gun a gun.

This led to a number of companies selling do-it-yourself firearm kits that contained all the components that make up a gun, except for the “frame”. They were legally considered only weapon parts, not actual weapons, and therefore not subject to the same controls.

Users could then use tools or a 3D printer to complete the kit by building their own receiver or frame, creating a usable gun that cannot be tracked.

Over the past decade, ghost weapons have been used in a number of high-profile crimes.

What havoc have they wrought so far?

The gun regulation group Everytown For Gun Safety lists 198 separate ghost gun shootings between June 2013 and September 2024.

In 2013, a 23-year-old man wielding a home-built AR-15-style rifle—who had previously passed a background check—killed five people and wounded two others in a shooting in Santa Monica, California.

2017 Another shooting rampage in rural Northern California killed four people and injured at least eight others, seven of whom were children. The killer circumvented a court order banning him from owning guns by building his own AR-15-style rifles at home, according to the police.

In 2023 a man carrying two ghost guns killed five people and wounded two in Philadelphiaprompting the city government to file a lawsuit against Polymer80 and JSD Supply, two suppliers of gun components.

The lawsuit claimed that approximately 87 percent of ghost guns seized by police as part of criminal investigations that year included parts made by Polymer80.

The two companies eventually settled the disputeearlier this year in April, they agreed to pay $1.3 million to gun violence prevention efforts and not sell their products to anyone in the city for the next four years.

What are the authorities doing about it?

Law enforcement agencies filed similar lawsuits, including the actions of two Los Angeles County sheriffs allegedly wounded in a 2020 ghost gun ambush.against Polymer80 and other companies,

Many states have also passed laws regulating home brewing firearms, including California, Colorado, Illinois, Nevada, New York and Pennsylvania.

In 2022, the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) adopted a new rule that defines DIY kits as firearms in their own right, meaning they were subject to the same regulations.

It also required federally licensed gun dealers who receive a firearm without a serial number to add their own traceable number before selling it to anyone else.

According to the Associated Press, these regulations have reduced the problem. Police seizures of ghost guns are reportedly down in major cities such as Philadelphia, New York, Los Angeles and Baltimore.

But gun kit manufacturers, backed by gun rights groups and attorneys general in Republican-controlled states, challenged this law, arguing that the ATF overstepped its legal bounds.

The Supreme Court is still challenging the law. It is unclear whether the court’s conservative supermajority will support or remove the new restriction.