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
4.
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
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