But chances are a pawnshop gun has been used, and no one wants a dirty gun. You never know where it's been. Federal guidelines suggest that all crime guns confiscated by police be turned over to the ATF to be traced. In 1999, ATF agents traced 7337 guns confiscated by New York City police. More than half of them were successfully tracked to their owners, according to an ATF report published last November 30.
Serial numbers are the easiest way to trace a gun.
Even if someone has tried to scratch out the engraved number or to burn it off with acid, forensics experts can sometimes still raise the number. If not, ballistics experts examine the bullets a gun has fired and the casings it has left behind. This was the method used on 950 of the New York guns traced by the ATF last year. A dirty gun is especially dangerous because, under federal and local law, the person caught holding the gun runs the risk of being held liable for any and all crimes to which the gun can be linked in any way, no matter how long he or she had it or who had it previously. For the guns traced by the ATF in 1999, the average amount of time lapsed between when the gun had last been used in a crime and when it had been taken by police was 7.2 years.