ULTRAVIOLET DETECTION OF METAL TRACES - TRACE METAL DETECTION TECHNIQUE - FINAL REPORT

• NCJ Number: 34019
• Author(s): J O RHOADS
• Date Published: 1971
• Length: 75 pages
• Grant Number(s): NI-71-015
• Sponsoring Agency: US Dept of Justice; US Dept of Justice NIJ Pub
• Corporate Author: Minnesota Dept of Public Safety
• Sale Source: National Institute of Justice/
• Language: English
• Country: United States of America

Annotation

THIS DOCUMENT CONTAINS THE RESULTS OF AN EVALUATION OF THIS TRACE METAL DETECTION TECHNIQUE UNDER CONTROLLED LABORATORY CONDITIONS AND THE RESULTS OF SURVEYS OF PARTICIPANTS IN FOUR WORKSHOPS HELD ON THIS TECHNIQUE.

Abstract

WITH THIS TECHNIQUE, SURFACES SUCH AS A PERSON'S HANDS OR CLOTHING ARE COVERED WITH A TEST SOLUTION, ALLOWED TO DRY, AND THEN EXAMINED UNDER ULTRAVIOLET LIGHT TO DETERMINE WHETHER THERE HAD BEEN RECENT CONTACT WITH METAL OBJECTS. IN THE LABORATORY TESTS, TEST SUBJECTS HELD METALLIC OBJECTS (PRIMARILY GUNS), FOR VARIOUS PERIODS OF TIME. THE SUBJECTS HANDS WERE TREATED WITH A TEST SOLUTION AND OBSERVED BY FOUR DIFFERENT OBSERVERS EACH OF WHOM UTILIZED FOUR DIFFERENT ULTRAVIOLET LIGHT SOURCES. THE RESULTS SHOWED THAT THE SUCCESS OF THE TECHNIQUE WAS RELATED TO VARIABLES SUCH AS LENGTH OF CONTACT, PRESSURE, AND MOISTURE. THE PERIOD OF TIME BETWEEN CONTACT AND TESTING WAS ALSO IMPORTANT. IN THE WORKSHOP SEMINARS, THE TRACE METAL DETECTION TECHNIQUE WAS PRESENTED TO 82 REPRESENTATIVES FROM LAW ENFORCEMENT IN 39 STATES. THIS REPORT CONTAINS THE RESULTS OF THREE SURVEYS OF THE PARTICIPANTS OF THESE WORKSHOPS. THE RESPONSES INDICATED THAT THE TRACE METAL DETECTION TECHNIQUE WAS FOUND TO BE OF VALUE IN APPROXIMATELY 50 PERCENT OF THE CRIMINAL INVESTIGATIONS IN WHICH IT WAS USED. THE APPENDIXES INCLUDE AN OUTLINE OF THE LABORATORY PROCEDURES USED AND RESULTS OF THE PARTICIPANT SURVEYS. (AUTHOR ABSTRACT MODIFIED)