Index
Dactyloscopy
1. Introduction p1
2. Discussion p1
2.1 Scenario p1
2.2. Definitions p1
2.3. Four basic categories of the ridge patterns p1
2.4. Classification of fingerprints p2
2.5. Identification and collection of fingerprints p2
2.6. Latent prints p2
2.7. Four Methods to develop latent prints p3
2.8. Photogrophy p5
2.9. Taking of fingerprints p5
3. Conclusion p5
Ballistics
4. Introduction p6
5. Discussion p6
5.1. Scenario p6
5.2. Definition p6
5.3. Ballistics p7
5.4. Classification of firearms p7
5.5. Classification of ammunition p8
5.6. Collection and recording of ballistic evidence p9
5.7. Examination of ballistic evidence p9
6. Conclusion p11
Tracks
7. Introduction p12
8. Discussion p12
8.1. SCENARIO p12
8.2. Protection of the crime scene p12
8.3. Categories of tire prints p13
8.4. Methods of recording prints p13
8.5. Test Impressions p16
9. Conclusion p16
ANNEXURE 1 p17
ANNEXURE 2 p18
ANNEXURE 3 p19
ANNEXURE 4 p20
Dactyloscopy
1. Introduction
Fingerprints are one of the most valuable types of physical evidence found at a crime
scene. Criminals often leave their ID cards at the scene of a crime. With the correct
equipment and skills of an investigator, it will be easy to connect a suspect to a specific
crime.
2. Discussion
2.1. Scenario
A burglar entered the house through a window. Pieces of glass lay on the ground, wet from
the recent rain. The house is a mess. Everything was thrown around in the search for
valuable items. Even the car in the garage was forced open with a screwdriver, which the
burglar left on the front seat.
A few days later a suspect was arrested after some stolen property from the burglary was
found in his possession. The suspect claims that he found the property in a dustbin near his
home. The fingerprint experts are called in to try to connect the suspect to the crime scene.
2.2. Definitions
2.2.1. Dactyloscopy
The science of identifying individuals by their fingerprints. The term is derived from the
Greek words dactylos that means finger, and copy that means print.
2.2.2. Fingerprints
The reproduction of the ridge areas of the first or nail joint of the finger in any manner.
2.3. Four basic categories of the ridge patterns
2.3.1. Arch
It consists of the plain arch and the tented arch, and consists of the parallel flow of ridges,
like wafes, from one side of the finger to the other side.
2.3.2. Loop
Some of the ridges makes a backward turn but without a twist. The loop can be ulnar or
radial.
2.3.3. Whorl
It is a pattern where at least one ridge completes a full circle.
2.3.4. Composites
Patterns where a combination of the arch, loop and whorl are found in the same print.
2.4. Classification of fingerprints
Classification can be described as the method to file or search for fingerprints.
Classification are done for the purpose of recording previous convictions, and the tracing
of unknown criminals. When finger prints are matched to a suspect, the expert will prepare
a court chart, indicating the 7 matching points. See annexure 1
2.5. Identification and collection of fingerprints
Searching for fingerprints at a crime scene must be conducted in a logical manner. Care
must be given to entrance and exit points.
The examiner must wear thin cloth gloves, and objects must only be touched by the edges.
Less obvious places like toilet handles, trunk lids and the back of rear view mirrors must
also be checked for prints. Frequently used objects normally dont deliver good prints. A
flashlight that is shined at a angle on a surface may help to reveal some fingerprints.
2.6. Latent prints
The term latent means hidden, but normally the term latent prints refers to those prints left
at crime scenes or on items of evidence. Latent prints can be seen or unseen and often
require development. Latent Print evidence can be divided into two main categories:
Porous and Non-porous.
2.6.1. Porous
Surfaces such as paper, unfinished wood and cardboard, is normally conducive to the
preservation of prints because the print residue can soak into the surface. This type of
evidence can absorb fingerprint residue into its surface. The investigator should not
attempt to process fingerprints on porous items of evidence. Laboratory processing
procedures and methods are best for this type of evidence. Little danger exists of
destroying latent prints on porous evidence, but a high possibility does exist of adding
additional latent prints.
All porous evidence must be placed in a paper envelope, plastic bag or a box and sealed.
The container must be marked with unique, identifiable markings.
2.6.2. Non-porous
Surfaces such as plastic, glass, metal and foil, is much more sensitive because the print
residue may just be lying on the surface. Even the slightest handling can destroy a latent
print on non-porous surfaces.
All nonporous evidence selected for latent-print examination should be processed as soon
as possible. If ridge detail is visible, photographs should be taken before any further
processing. Send only the photographs taken before lifting and the actual lifts. Do not
submit evidence to the laboratory if the investigator has powdered the latent prints and
they are capable of being lifted.
Another category of latent prints is patent prints and plastic prints.
2.6.3. Patent prints
Impressions that are visible in some form of contaminant like blood or grease.
2.6.4. Plastic prints
Impressions left in soft materials like wax, window putty, or other pliable materials
2.7. Four Methods to develop latent prints
2.7.1. Traditional powders
Traditional powders come in a number of colors like black, white, silver, red and grey. A
darker powder must be used on lighter surfaces to create contrast. According to Osterburg
& Ward (1992:109), Duel-use powders are available and will appear black on a light
colored surface, and silver on a darker surface. The prints are lifted with folien, or normal
3M tape. See annexure 3
2.7.2. Fluorescent powders
Low concentrations of some substances will cause the print to glow under laser or
