Forensic importance of tool marks

1. TOOL MARKS
Submitted by Submitted to
V. Rohit Ketan Sir

2. OVERVIEW
 Tool marks
 Types of tool marks
 Location
 Collection
 Packing
 Evaluation
 Importance

3. TOOL MARK
 A tool mark is defined as the impression left by the contact of a tool or similar object on to a
surface
 TOOLS & Weapons
 It is knives, razor blades , axes ,hammers ,screw drivers ,hacksaws ,spades or sharp metallic
implement
 Tools leave distinctive marks because they are generally made of metals harder than the
surface with which they normally come in contact
 Tool marks which are cut marks ,drill marks ,struck marks, levering marks, shear mark,
depressed marks etc.
 Tool marks are more or less permanent, hence the same can be used to link the criminal with
the crime scene ,even after long time

5. TYPES OF TOOL MARKS
 Compression or ( indented) tool marks
 Sliding tool marks
 Cutting tool marks

6. COMPRESSION TOOL MARKS
 When a tool is pressed into softer material
 Such marks often show the outline of the working surface of the tool, so the class
characteristics of the tool ( such as dimensions) can be determined

7. SLIDING TOOL MARK
 It is created when a tool slides along a surface
 Such marks usually consist of pattern of parallel striations class characteristics are more difficult
to determine from sliding tool marks

8. CUTTING TOOL MARKS
 It is the combination of compression and sliding tool marks
 The cutting tool indents the material being cut and it does the working surfaces of the tool
slide over the cut surfaces

9. LOCATION
 Tool marks are often present in crime involving breaking on an entering they may be found
on the locks of doors or windows that a criminal has jimmied in order to gain entrance
 the cut marks on the clothes caused by knives are very common.
 Holes made in the walls by the knives or other implements

10. COLLECTION
 Whenever possible , the original articles bearing the questioned tool marks are collected
 Similarly all suspected likely tools should be collected
 When the articles is too big for convenient handling the mark bearing portion (of wood, metal
and masonry work )is cut separated sealed and sent in the usual way
 Cast
 Adhesive tape
 Plaster of Paris

11. PACKAGING
 The packing of the evidence should ensure safety against breakage contamination and
loss
 The marks in no case should come in contact with the packing material
 If the climate is humid and hot a tool or the mark on iron and steel articles may rust the
mark may get damaged

12. EVALUATION
 It is a tool mark examiner makes microscopic comparisons of the test tool mark and
questioned tool mark in order to match marking
 As is the case with fire arms examination tool mark examiner can reach one of three
conclusions
 Positive identification
 Negative identification
 inconclusive

13. IMPORTANCE
 Permanency
 Individuality
 Linkage
 reconstruction

14. REFERENCE
 Book B . R. Sharma of forensic science in criminal investigation
 Book by Max M Houck and Jay A Siegel
 Book by forensic science and its related issues

15. THANK YOU