/Ghost gun used in Saugus High School shooting. What is it and is it legal?

Ghost gun used in Saugus High School shooting. What is it and is it legal?

A teen who fatally shot two students and injured three others in Santa Clarita, California, used an unregistered “kit gun” in last week’s shooting, authorities say.

Kit guns, sometimes called “ghost guns” if they do not have a serial number, are self-assembled firearms, according to the Giffords Law Center to Prevent Gun Violence.

Los Angeles County Sheriff Alex Villanueva told KABC-TV that the gun used in the shooting at Saugus High School does not have a serial number to track.

“The real concern here is that you have untraceable, unserialized firearms that exist completely outside of the regulatory scheme of federal and state law,” Nick Suplina, managing director for law and policy at gun violence group Everytown, told USA TODAY.

“People who are prohibited from owning firearms under federal or state law have ready access to make their own untraceable firearms, and that’s very dangerous.”

‘Ghost gun’ used:Santa Clarita gunman used unregistered ‘ghost gun’ in Saugus High School shooting, sheriff says

Here’s what to know about ghost guns:

What makes ghost guns dangerous compared to other firearms?

Ghost guns are dangerous because they are untraceable, can be made from plastic parts and do not require a background check, says the Giffords Law Center to Prevent Gun Violence.

With traditionally manufactured firearms, gun makers or importers affix a serial number and markings to the gun that identify the manufacturer or importer, make, model and caliber, the center says.

The Bureau of Alcohol, Tobacco, Firearms and Explosives can then trace these guns to their first retail purchaser when investigating a crime.

However, those who make kit guns and parts can say they are not selling an actual firearm and are not required to use a serial number under federal law, which makes the chain of custody near impossible to track, the Giffords Law Center says.

While some kit guns may have a serial number attached to them, Suplina says most are untraceable and, therefore, ghost guns.

Buyers of ghost guns do not face federal background checks either because they are purchasing “unfinished” frames or receivers.

Suplina says the federal government considers frames or receivers – which houses other parts, including the firing mechanism – the part of the gun that makes it a firearm and requires a serial number and background check to purchase. If a receiver is considered unfinished under federal purview, though, it is not regulated like a firearm, he says.

Some of these firearms may also be made with plastic parts. This makes them undetectable to traditional metal detectors, the Giffords Law Center says.

Where do ghost guns come from?

Kit guns can be sold online or at gun shows, Villanueva told KABC-TV. Buyers can then use simple tools to build the firearm, according to Newton Action Alliance.

“They’re also known as an 80% gun. So 80% of it is assembled already and you also get the additional 20%,” Villanueva told the TV station. Some are sold as a package with all the parts and tools needed to complete the firearm, Suplina said.

“You’re essentially ordering a firearm, but just completely outside the rule of law,” Suplina added.

Some untraceable guns may also be 3D printed. According to the Giffords Law Center, the models and printers can be purchased for around the same cost of a traditionally manufactured firearm.

Newton Action Alliance says in some cases, these firearms can be made from almost entirely from plastic parts, except for a metal nail used as a firing pin.

Are ghost guns illegal?

Federal and some states’ laws prohibit some undetectable firearms, the Giffords Law Center says.

The Undetectable Firearms Act requires that guns are detectable by metal detectors “after removal of grips, stocks, and magazines,” and that X-rays can detect all major components, including “the barrel, the slide or cylinder, or the frame or receiver.”

However, a person could make a complaint gun with largely plastic parts and some metal parts that are easily removable before entering a security area, the center says.

Additionally, ATF determines if a product is a firearm that requires a background check and serial number or if it is an unfinished kit and requires no check or serial number.

California passed regulations in recent years that require self-assembled firearms to have serial numbers, among other restrictions. New Jersey also prohibits the sale of firearm parts that “may be readily manufactured or otherwise assembled” without a serial number. Those who want to use a 3D printer to build a gun must also be a registered or licensed firearm manufacturer or dealer, the Giffords Law Center says.

How did the Santa Clarita shooter obtain one?

It is unknown who bought the pistol’s parts or put it together, Los Angeles County Sheriff’s Lt. Brandon Dean said in a statement.

Authorities found several other unregistered guns in his home in Santa Clarita, near Los Angeles. They are investigating where the guns came from, and noted registered guns belonging to his father were seized in 2016.

Previously, Villanueva said the 16-second shooting blitz was deliberate and the shooter seemed familiar with the weapon. The gun jammed at one point, but he quickly cleared it.

Contributing: Kristin Lam, USA TODAY. Follow USA TODAY’s Ryan Miller on Twitter @RyanW_Miller