NCJ Number
55558
Journal
Journal of the Forensic Science Society Volume: 18 Issue: 1 & 2 Dated: (JANUARY/APRIL 1978) Pages: 31-46
Date Published
1978
Length
16 pages
Annotation
A LABORATORY METHOD FOR EXAMINING SAW MARKS IS PRESENTED. IT CONSISTS OF THREE STAGES: DETAILED EXAMINATION OF THE SAWN SURFACE, PREPARATION OF SUITABLE TEST MARKS, AND EXAMINATION OF THE SUSPECT SAW.
Abstract
SAWS ARE USED IN A VARIETY OF CRIMES SUCH AS MURDER, ARMED ROBBERY, SAFE BREAKING, FORCED ENTRY, THEFT, AND VANDALISM. FORENSIC INVESTIGATORS WILL NEED TO ESTABLISH MANY CHARACTERISTICS OF THE SAW PROBABLY USED IN A CRIME AND THE WAY IN WHICH IT WAS USED. THEY SHOULD CAREFULLY STUDY CONTACT TRACES, THE STRIATION PATTERN--INCOMPLETE AND FINAL CUTS, AND THE MAIN AREA OF THE MARK. TEST MARKS SHOULD BE MADE IN MATERIAL SIMILAR TO THAT OF THE EVIDENCE AND WITH BLADES HAVING CLOSELY RELATED FEATURES. EXAMINATION OF THE SUSPECT SAW (WHEN AVAILABLE) BEGINS WITH A GENERAL EXAMINATION OF THE SAW AS A WHOLE AND THE BLADE IN PARTICULAR, NOTING FEATURES SUCH AS TYPE OF FRAME, METHOD OF INSERTION OF THE BLADE, AMOUNT OF TENSION ON THE BLADE, CONDITION OF THE BLADE AND INDIVIDUAL TEETH, AND SIGNS OF ALIEN PAINT. ANALYSIS OF EVIDENCE USING THESE GUIDELINES SHOULD REVEAL INFORMATION ON NUMBER OF TEETH PER UNIT LENGTH IN THE SAW, THE MANUFACTURER, CONDITION OF THE BLADE OR TEETH, AND SOME EVIDENCE ABOUT THE SAWING ACTION. THREE CASE STUDIES ARE DISCUSSED. INFORMATION ON MATERIALS NECESSARY FOR SUCH AN EXAMINATION, ILLUSTRATIONS OF VARIOUS TYPES OF BLADES AND SAW MARKS, DATA ON MAIN FEATURES OF TYPES OF SAWS COMMONLY AVAILABLE IN THE UNITED KINGDOM, AND REFERENCES ARE PROVIDED. (DAG)