Ghost guns are virtually untraceable weapons.
The unserialized firearms can be easily assembled at home using parts purchased online.
"They're becoming more prevalent," said Brendan Iber, the Special Agent in Charge of the ATF's Phoenix office.
The Privately Made Firearms (PMFs), as the ATF refers to them, are not just sitting in locked safes.
"They're definitely circulating in the criminal world, and I think it's more than we know," said Iber.
This past November, Phoenix police said a 15-year-old bought a "ghost gun" from a fellow Cesar Chavez High School student using counterfeit cash. After the 16-year-old seller realized he had been duped, he got upset. Investigators said that is when the younger boy, who just purchased the gun, shot the other.
"The gun that was sold is a poly-type gun, often referred to as a ghost gun," said Sgt. Ann Justus.
The Phoenix Police Department told ABC15 that between 2021 and May 2022, they recovered and processed 91 "ghost guns."
The White House said earlier this year that ghost gun seizures have increased ten-fold since 2016.
"[These] can go from a gun kit to [a] gun in as little as 30 minutes. Buyers aren't required to pass background checks because [ghost] guns don't have serial numbers," said President Joe Biden at an April news conference.
The lack of manufacturing and tracking standards produces a unique challenge for agents.
"When it's not serialized, it makes our job difficult to figure out where that firearm started," said Iber.
"Are you pulling these [ghost guns] off the streets with some regularity?" asked ABC15's Zach Crenshaw.
"Yes, we are. Right now, it's very small, though."
Iber said ghost guns only account for 0.98% of all firearms recovered by law enforcement.
He says part of that is education.
"A lot of police departments just don't know what they're looking at, because usually, you'll have the frame or receiver of the firearm that is not serialized, but you have to bring parts from other areas," said Iber, who explained that a ghost gun can sometimes look like a legitimate Glock.
"Do you have any idea how many are being made a year?" asked Crenshaw.
"No," replied Iber. "And that's what we're trying to wrap our head around."
In the most recent ATF 'Firearms Commerce and Tracking Assessment,' the federal agency noted, "It is probable that current trace data significantly under-represents the number of PMFs recovered in crimes by law enforcement..."
The report states that the two main reasons for the lack of accurate data are "law enforcement is just beginning to institute uniform training on the recognition, identification, and reporting of PMFs" and the guns "by their nature may have no markings at all."
In May 2022, the Biden administration unveiled a new rule requiring ghost gun kits to have serial numbers and buyers to be background checked.
In theirpress release, the White House wrote: "This rule clarifies that these kits qualify as “firearms” under the Gun Control Act, and that commercial manufacturers of such kits must therefore become licensed and include serial numbers on the kits’ frame or receiver, and commercial sellers of these kits must become federally licensed and run background checks prior to a sale – just like they have to do with other commercially-made firearms."
That law officially goes into effect in August.
Iber told ABC15 his agents, and every cop across our state, are less concerned about the make and model of a gun.
"Any firearm that's in the hands of a criminal, concerns us. It doesn't matter if it's a ghost gun, it does not matter if it's a firearm that started in legal commerce and came into illegal."