Para verem que não estava brincando. leiam o artigo inteiro.http://forensics4fiction.com/2011/09/09 ... -firearms/
Criminals using stolen weapons sometimes make efforts to deface or destroy that serial number (which is a crime) so police can not trace it back to the original owner. The gun may be from a relative, friend, or may link them to another crime such as burglary. There are a variety of ways a criminal might deface a serial number including grinding, drilling, hammering, and punching.
These efforts may make the numbers unidentifiable to the naked eye and criminals usually stop when they can not make out the numbers (just as they may stop cleaning when they stop seeing blood).