NCJ Number
61543
Date Published
1979
Length
18 pages
Annotation
THE PRACTICAL EXPERIENCES OF 3 YEARS' CASEWORK WITH SCANNING ELECTRON MICROSCOPY (SEM) ARE EXAMINED. THIS REVIEW COVERS ANALYSIS OF CLOSE TO 1,500 ITEMS OF EVIDENCE.
Abstract
THE TYPES OF CRIME, THE KIND OF MATERIAL AND THE TECHNIQUES USED ARE DISCUSSED. PRODUCED BY A FORENSIC LABORATORY IN SWEDEN, THE REVIEW EXAMINES THE TREND OF EXPANDING SEM TECHNIQUES TO INVESTIGATIONS TRADITIONALLY CARRIED OUT BY OTHER METHODS. THE IMPORTANCE OF CORRECT EVIDENCE COLLECTION IS STRESSED. A POLICY CHANGE REGARDING THE USE OF THE SEM ALLOWED ITS USE IN ROUTINE CASES. EXPERIENCE WITH IT REVEALED THAT SEM ANALYSIS USUALLY IS FASTER AND LESS EXPENSIVE THAN MANY OTHER TECHNIQUES. THE INSTRUMENT USED IN THIS LABORATORY IS A JEOL JSM-35 EQUIPPED WITH A PRINCETON GAMMA TECH ENERGY DISPERSIVE X-RAY ANALYZER CONNECTED TO A 'SERVOGOR' X-RAY RECORDER. COATINGS WERE DONE IN A JEOL VACUUM EVAPORATOR. PAINT CHIPS, SMEARS OF PAINT ON TOOLS, AND GLASS FRAGMENTS ARE THE MOST COMMON MATERIALS ANALYSED FOR BURGLARY CASES. SEM TECHNIQUES MAY ALSO BE USED IN ARSON INVESTIGATION (ANALYSIS OF WIRES AND CONTACTS), FRAUD INVESTIGATION (DOCUMENT AND COIN ANALYSIS), HOMICIDE INVESTIGATION (GUNSHOT RESIDUE, BULLETS, FIBER ANALYSIS), AND INVESTIGATION OF CRIMES INVOLVING JEWELRY AND PRECIOUS METALS. SEM IS USED ALSO TO IDENTIFY THE INORGANIC CONSTITUENTS OF SMAPLES REMAINING FROM BOMBINGS. TABLES SHOW THE NUMBER OF ROUTINE CASES HANDLED BY SEM BETWEEN JULY 1975 AND DECEMBER 1977, THE CASES GROUPED BY TYPE OF CRIME SUSPECTED, AND TYPES OF MATERIALS INVESTIGATED. PHOTOGRAPHS, AND REFERENCES IN ENGLISH AND GERMAN ARE INCLUDED. (RFC)