What is a ghost gun, and how police say they were used in Philadelphia mass shooting

Authorities said the man accused of the mass shooting that left five dead and two children injured in a Philadelphia neighborhood on July 3 used a ghost gun.

These so-called ghost guns, or largely untraceable weapons, are making it harder for authorities to combat gun crime an solve cases, officials said,

Philadelphia Police Deputy Commissioner Frank Vanore said the AR-15 used in the shooting and a 9mm handgun Kimbrady Carriker was carrying, but which wasn’t used during the spree, were ghost guns.

“So if he would have dropped that weapon and got away, we would have had no way to trace that weapon back to him,” Vanore said.

Philadelphia mass shooting: 5 dead, 2 injured after shooting in Philadelphia; suspect in custody

What is a ghost gun?

They are privately-made firearms without serial numbers.

Generally, firearms manufactured by licensed companies are required to have serial numbers — usually displayed on the frame of the gun — that allow officials to trace the gun back to the manufacturer, the firearms dealer and original purchaser.

Ghost guns, however, are made of parts and are then assembled together. The critical component in building an untraceable gun is what is known as the lower receiver. Some are sold in do-it-yourself kits and the receivers are typically made from metal or polymer.

An unfinished receiver — sometimes referred to as an “80-percent receiver” — can be legally bought online with no serial numbers or other markings on it, no license required. Under the current rules, the federal government does not consider unfinished lower receivers to be firearms.

More: How a traffic stop took down an alleged Bucks County ghost gun 'empire'

How do authorities say ghost guns were used in a mass shooting in Philadelphia?

At a news conference Wednesday afternoon Philadelphia officials announced a lawsuit against several makers of self-made gun kits and gun parts, officials said that both guns found on Carriker after he was taken into custody appeared to be self-manufactured — commonly called ghost guns.

Carriker is accused in the fatal shooting spree in Philadelphia that left five people dead and four others wounded Monday night. Police said he left a will at his house, and according to a roommate had acted agitated and wore a tactical vest around his house in the days before the shooting, prosecutors said Wednesday.

Carriker was arraigned Wednesday morning on five counts of murder, attempted murder, aggravated assault and weapons counts of possession without a license and carrying firearms in public, prosecutors said. The 40-year-old is accused of killing a man later found dead inside a house and then gunning down four others before surrendering to police.

A 2-year-old boy and a 13-year-old youth were also wounded by gunfire and another 2-year-old boy and a woman were hit by shattered glass in the rampage that made the working-class area in southwest Philadelphia the site of the nation’s worst violence around the July Fourth holiday.

Mayor Jim Kenney said Wednesday that the city has seen a nearly 300% increase in ghost guns recovered during police investigations over the past four years, including 575 recovered in 2022.

More on ghost guns: A soaring number are being used in crimes, report finds

How prevalent are ghost guns?

Ghost guns aren’t new. But they are becoming a growing problem for law enforcement agencies across the U.S.

Federal officials have been sounding the alarm about the growing black market for homemade, military-style semi-automatic rifles and handguns. And guns without serial numbers have been turning up more frequently at crime scenes. They have also been increasingly encountered when federal agents buy guns in undercover operations from gang members and other criminals.

The sale of ghost guns has exploded since then. It is hard to say how many are circulating on the streets, in part because in many cases police departments don’t contact the government about the guns because they can’t be traced.

Through executive order in 2021, President Joe Biden directed his administration to tighten restrictions on ghost guns that can be constructed from parts purchased online.

This article originally appeared on Bucks County Courier Times: What is a ghost gun? Philadelphia mass shooting update