Daniel Webster, a professor at the Johns Hopkins University Bloomberg School of Public Health, identified an executive order by President Joe Biden requiring “ghost gun” kits to have serial numbers.

Aiming to crack down on these weapons, the Bureau of Alcohol, Tobacco, Firearms, and Explosives updated its regulations on how firearms are defined to include ghost guns. ATF clarified that parts kits ...

The standard background check for those buying a gun would have turned up red flags, including an illegal weapons violation from four years earlier. But there was no check. The weapon was a so-called ...