A Baltimore Police Department SWAT team gathered outside of a McElderry Park rowhome on Dec. 29, 2022, preparing to break down the door. Inside, the officers had learned, was a man who had been 3D-printing gun parts en masse for weeks.

After they busted down Kevin Wallace’s door, police found dozens of 3D-printed handgun components, an assortment of pieces in a variety of colors that could be readily assembled into a usable weapon. The handgun frames and receivers were in pink, green, gray, tan, even “Tiffany blue,” according to court records. Some were hanging like ornaments on an artificial Christmas tree.

Fast forward a year and a half and federal prosecutors are seeking to send Wallace, 40, to prison for two years, according to court records.

In March, Wallace pleaded guilty to a charge of prohibited possession of ammunition, a charge for people who previously committed felonies and are banned from owning a gun or bullets. An attorney representing Wallace could not be reached for comment Tuesday.

The Baltimore Banner thanks its sponsors. Become one.

“These firearm parts in the wrong hands would only serve to exacerbate the already dire firearm and violence problem in Baltimore City,” prosecutors wrote in Wallace’s sentencing memo. “Therefore, not only was it illegal for Wallace to possess the 9mm ammunition found in his home, but it was dangerous and reckless for the public for Wallace to be producing these privately made firearm parts en masse.”

Originally, Wallace was charged in state court with a host of gun crimes related to the raid on his home where police also seized a 3D printer and various high-capacity magazines he made. His case was transferred to federal court, where he was indicted on the prohibited possession of ammunition charge.

The gun parts seized from Wallace’s home are part of a larger problem facing Baltimore. Guns that are made from 3D-printed parts tend to lack serial numbers, meaning their origins can’t be traced.

Also known as “ghost guns,” they have flooded city streets. A Baltimore Banner analysis found 1 out of every 5 guns police recovered from June 2021 to June 2023 was a ghost gun. That count doesn’t include guns that had their serial numbers obliterated or filed off, only guns that were built without one. So common are the unserialized weapons that police, over the same time period, recovered more of them than Glocks.

1 in 5 guns on Baltimore’s streets don’t have serial numbers. That’s a problem.

3D-printed guns are less common, and police are less likely to make busts like the McElderry Park arrest without tipsters or informants. In Wallace’s case, his social media posts led police to him.

The Baltimore Banner thanks its sponsors. Become one.

In one Instagram video, according to court records, Wallace filmed himself standing next to the steps of his home holding a firearm with a homemade attachment converting it into a rifle. In another video, Wallace filmed his 3D-printer whirring away, creating a lower receiver — the part of the gun that contains the trigger, grip and firing mechanism.

Ghost guns have been recovered in every corner of the city and have been used in high-profile killings. The teenage squeegee worker who shot and killed baseball bat-wielding Timothy Reynolds near the Inner Harbor in 2022 used a ghost gun. So did the gunman who killed Safe Streets worker Dante Barksdale in 2021.

In February, Mayor Brandon Scott reached a settlement with Polymer80, the largest ghost gun parts manufacturer, that effectively ended the company’s business in Maryland.