California state Senator Kevin de Leon proposed a bill on Monday that would require anyone who plans to assemble a gun made from a 3D printer to undergo a background check, the Associated Press reported. The bill also extends to anyone buying parts of a gun to assemble at home.

The 3-D printer allows anyone to download gun designs and build it without any type of safeguard, the AP reported.

A similar California law already in place states gun owners and buyers need to undergo a background check before buying and register their weapon after its bought, according to the AP.

De Leon hopes to prevent the over popularization of guns made out of 3D printed parts, which can also go undetected when passed through a metal detector because it's made out of plastic, the AP reported.

The two issues being tackled nation wide in preventative measures are what De Leon calls a "twin threat": plastic guns made from 3D printers which can go undetected through metal detectors and unregistered weapons being used by people who are not allowed to own firearms under state law, the AP reported.

"Currently, no one knows they exist until after a crime has been committed," de Leon said, according to the AP.

If de Leon's proposed bill is passed and works, cases like that of John Zawahri may be prevented, according to the AP. Zawahri built a 3-D rifle after he was prohibited from buying a gun in California due to mental illness and went on a killing spree last June killing five people.

De Leon's proposed bill, SB 808, states that only those who apply to the state Department of Justice for a serial number, which they will only get after the applying gun buyer undergoes a background check, will be allowed to legally manufacture or assemble guns at home, the AP reported.

The serial number would have to be attached to the gun or engraved at all times and would need to be placed on the firearm within a day of its production, according to the AP.

An existing ban on plastic firearms that can go undetected through metal detectors and X-ray machines was also extended for the next 10 years by the federal government, the AP reported.

De Leon said he also plans to add another amendment requiring guns made of plastic to contain a piece of metal so it may be detected by X-ray machines and metal detectors, the AP reported. That proposal was previously blocked by the federal legislation.

National Rifle Association spokeswoman Catherine Mortensen said though the organization did not oppose the 10-year extension to the ban prohibiting plastic firearms, they would oppose any type of amendment to the law at state, or federal, level, according to the AP.