The trace starts with a call or fax to the National Trace Center in Martinsburg, West Virginia. A police department has recovered a gun at a crime scene that was bought at a dealer that has since gone out of business. The inquiring officer turns to the Bureau of Alcohol, Tobacco, Firearms, and Explosives to find out who purchased it, and when. Federally licensed gun dealers are required to submit sales records to the ATF when they close up shop. The ATF has acquired a... (GunPolicy.org)