The assessment of experimental methods of serial number restoration.

Abstract

Serial number restoration is a common and successful process of revealing obliterated serial numbers on firearms. In a crime laboratory setting, obliterated serial numbers are commonly processed in order to tie a person to a crime scene or provide an investigative lead for officers. Currently serial numbers are restored using a chemical etchant method that can eat away at the metal on the firearm even after the examination is complete. It can also take several hours to complete and only provide an examiner with a partial number. There are other nondestructive options however little to no literature is available. The purpose of this study is to discover new methods for nondestructive serial number restoration and to compare them to the traditional chemical method used. Metal bars of premeasured obliteration depths and different compositions were examined using three proposed experimental methods: near infrared imaging, cold frost, and scanning acoustic microscopy. Results did not indicate significant difference in the median number of visible digits recovered for each of the three proposed methods compared to the traditional chemical method. There were significant results in the median number of composition utilized and depth of obliteration. This indicates that different firearm compositions and depth of obliteration has an effect on serial number restoration..