The Supreme Court on Wednesday made a key ruling on the nearly impossible-to-trace weapons called “ghost guns.”

That decision upholds a Biden administration regulation, clearing the way for continued serial numbers, background checks, and age verification requirements for buying the kits online.

“We typically see folks do that at home,” says Brooklyn Park Deputy Police Chief Elliot Faust. “It’s very easy to do; you can make a working firearm in short order.”

RELATED: Brooklyn Park PD sees more ghost guns on streets; new federal rules expected soon

The 7-2 opinion found that existing gun laws allow regulation of the kits increasingly linked to crime.

It comes after President Donald Trump ordered a review of federal gun policy that could undermine or reverse regulations championed by his predecessor.

Sales of homemade firearms grew exponentially as kits allowing for easy at-home building came into the market, Justice Neil Gorsuch wrote in the majority opinion. “Some home hobbyists enjoy assembling them. But criminals also find them attractive,” he said.

The number of ghost guns found at crime scenes around the country has also soared, according to federal data.

Fewer than 1,700 were recovered by law enforcement in 2017, but that number grew to 27,000 in 2023, according to Justice Department data.

Brooklyn Park Police say typically, they confiscate between twenty and thirty ghost guns a year.

A big concern is juveniles getting a hold of the kits.

In 2023, Brooklyn Park Police Officers investigated the shooting death of a 16-year-old.

The murder weapon was made from a gun kit purchased by another juvenile online.

“It was purchased as gun parts, assembled, as simple as using a hand-held drill and made a working firearm that took somebody’s life,” Faust says. 

Since the federal rule was finalized, though, ghost gun numbers have flattened out or declined in several major cities, including New York, Los Angeles, Philadelphia, and Baltimore, according to court documents.

The manufacturing of miscellaneous gun parts also dropped 36% overall, the Justice Department has said.

The most recent numbers from Minneapolis Police show that in 2024, officers recovered 83 ghost guns made by a 3D printer.

Ghost gun seizures reached a peak in 2022 at 111. That compares to just three recoveries in 2019.

Ghost guns are any privately made firearms without the serial numbers that allow police to trace weapons used in crime.

The 2022 regulation was focused on kits sold online with everything needed to build a functioning firearm — sometimes in less than 30 minutes, according to court documents.

“For a fifteen-year-old, sixteen-year-old, to be able to order online, it’s literally that simple,” Faust explains. “Put in a credit card number, get these gun parts shipped to you, use a hand-held drill and drill four holes, and you have a working firearm.”

Ghost guns have been used in high-profile crimes, including a mass shooting carried out with an AR-15-style ghost gun in Philadelphia that left five people dead.

Police believe a ghost gun used in the slaying of UnitedHealthcare’s CEO in Manhattan was made on a 3D printer rather than assembled from a kit of the kind at the center of the Supreme Court case.

Finalized at the direction of then-President Joe Biden, the “frame and receiver” rule requires companies to treat the kits like other firearms by adding serial numbers, running background checks and verifying that buyers are 21 or older.

Gun groups challenged the rule in court in the case known as Garland v. VanDerStok.

Most crimes are committed with traditional firearms, not ghost guns, they argued.

It’s legal for people to build their own firearms at home, the challengers said, arguing that the Bureau of Alcohol, Tobacco, Firearms and Explosives overstepped its authority by trying to regulate the kits.

“Still, there is a serious second amendment challenge here, which was not decided today, and is the obvious next part,” says Cody Wilson, founder of Defense Distributed.

The Supreme Court majority disagreed, pointing out that the law gives the ATF the power to regulate items that can be quickly made into working firearms.

“The ‘Buy Build Shoot’ kit can be ‘readily converted’ into a firearm too, for it requires no more time, effort, expertise, or specialized tools to complete,” Gorsuch wrote, referring to a specific product.

Some kits may take more time to build into guns and therefore fall outside the ATF’s power, he wrote, but many popular kits are subject to regulation.

“While this decision did not address the legality of privately manufactured firearms, rather ATF rulemaking authority, we are concerned that this ruling significantly broadens the ATF’s ability to interpret statutes to fulfill its regulatory objectives,” says Rob Doar, with the Minnesota Gun Owners Caucus. “It is now up to the current administration to decide whether to uphold this rule or return to the pre-2022 framework.”

In response to the ruling, a Justice Department spokesperson said the administration would “continue to support and defend the Second Amendment rights of all Americans.”

Gun safety groups celebrated the ruling, with Everytown Law executive director Eric Tirschwell saying the rule also had broad support from law enforcement. “Fundamentally, today’s decision confirms the ghost gun industry is dead as a viable business model,” he said.

The court previously expanded Second Amendment rights with a finding that modern gun regulations must fit within historical traditions.

The justices also struck down a firearm regulation from President Donald Trump’s first administration, a ban on gun accessories known as bump stocks that enable rapid fire.

In a dissent, Justice Clarence Thomas wrote that the ghost gun rule should meet the same fate. The kits, he wrote, are only firearm parts and shouldn’t be subject to a regulation that could open the door to rules on other popular weapons. “Congress could have authorized ATF to regulate any part of a firearm or any object readily convertible into one,” he wrote. “But it did not.”

In 2023, the Minnesota Supreme Court ruled that a gun that’s been taken apart and is missing pieces can still be considered a firearm under state law.

Minnesota already has a rule on the books requiring serial numbers on all firearms.

Still, Faust hopes the new ruling will make a difference.

“Tracking of firearms is important to us when we’re trying to solve crimes,” he says. “At a very basic level, we don’t want juveniles to possess firearms.”

The Associated Press contributed to this report.