In a chilling new report, the Bureau of Alcohol, Tobacco, Firearms and Explosives revealed that the number of privately-made firearms identified by law enforcement doubled between 2020 and 2021. Owners of these “ghost guns” assemble them piece by piece and, as a result, they do not have serial numbers and cannot be traced by law enforcement, Axios reports. Law enforcement recovered 19,273 of these firearms in 2021, a sizeable jump from 8,504 in 2020, according to the report. Over 38,000 suspected “ghost guns” were recovered in total from 2017 and 2021, according to Axios. The Bureau also noted an uptick in the criminal use of these guns. Their report marks “one of the most sweeping looks at guns and crime in the U.S.” in over 20 years, Axios reports.