Along with attorneys general from 19 states and the District of Columbia, California Attorney General Rob Bonta backed a new federal rule against phantom guns in an amicus brief filed Monday.

The amicus brief, which is an opinion submitted to the court by a party uninvolved in a case but carries weight, was backed by Bonta in the wake of the mass shootings and the rise of phantom guns, his official said. desk.

Ghost guns are privately made firearms without a serial number, making them essentially untraceable for law enforcement. Flying under the radar of state requirements, unlicensed owners and manufacturers waive background checks and ownership registrations of these illegally produced firearms.

The US Department of Justice said the number of ghost weapons seized by law enforcement has increased tenfold since 2016. Last year alone, 20,000 suspected ghost weapons were reported to the Bureau of Alcohol, tobacco, firearms and explosives.

In response, the Biden administration issued a federal rule in April to expand gun regulations to include homemade guns and easy-to-assemble gun kits. The rule, which comes into effect next month, will require buyers to pass background checks and manufacturers to license and produce serialized gun kits.

The rule has since been challenged by a Texas-based gun parts maker, who argue the rule is not legally valid and threatens the makers’ ability to stay in business.

The group of attorneys general, along with Bonta, say state regulations must be backed by meaningful federal oversight.

“There have been more mass shootings nationwide than days a year in 2022. In California, we know our safeguards are working, but we need to see such actions nationwide,” he said. Bonta said in a statement.

In California, law enforcement seized 12,388 ghost guns last year, up from 26 in 2015.

Although California has the 44th-lowest gun death rate in the nation, it is no exception to fatal shootings involving ghost guns. A recent example took place in March 2022, when a shooter banned from buying firearms killed his three children, a chaperone and himself at a church in Sacramento. Or in 2019, when five students at Sagus High School were gunned down, two of them killed, by their 16-year-old classmate with a kit-made weapon.

“I support stronger federal efforts to curb the gun violence that is sweeping our country and the killing of thousands of Americans, including children,” Bonta said. “We refuse to accept that gun deaths are somehow normal when we know there are strategies to stop them. My office will continue to use all legal tools available to end this epidemic of violence. military and to keep Californians safe.”