XI.

HAND-OUT ON HAIR AND TEXTILE FIBER

Hair examination is one of the oldest forms of physical evidence. Its use is older than fingerprints. It is valuable because the hair
of each kind of animal is different and distinct for all others. Like fiber it is most likely to be involved in contact between the victim
and the suspect. Most crimes cause contact between one person and another and there may be a transfer of fibers and hairs from the
victim to the criminal and vice-versa. The successful investigation of crimes of violence such as rape, murder, assault, kidnapping, hit
and run, etc. are frequently materially assisted by the result of the examination of the hairs and fibers. Hairs are very resistant to
decomposition and putrefaction thus they often remain as a means of identification long after such as facial and fingerprints have been
destroyed.

Hair – a structure that grows out of the pores of the skin and covers the different parts of the body except for the palm of the hands
and sole of the feet. It is made out of keratinous material similar to that which makes up nails.

Two (2) Kinds of Hair (among mammals including human being).

1. Real Hair. Generally long and stiff.
2. Fuzz Hair. Generally short, fine at times curly and wooly.

Parts of the Hair

Anatomically hair is consisting of three (3) parts namely:
1. Root. Portion embedded in the skin
2. Shaft. Portion above the surface of the skin. It is the most distinctive part of the hair.
3. Bulb. Consist of epithelial cells and is swelling at the base where the hair originates in the dermis.

The Human Hair

Parts of the Shaft

1. Cortex. The intermediate and the thickest layer of the shaft and is composed of elongated, spindle shaped fibrils which
cohere. They contain pigment granules in varying proportion depending on the type of the hair.
2. Cuticle. Outermost covering of the hair. It consists of one layer of non-nucleated polygonal cells which overlaps like the
scales on fish.
3. Medulla or Core. The central canal of the hair that may be empty or mat contain various sorts of cells more or less
pigmented and begins more or less near the root.

Classification of Hair into Two (2) Categories

1. Hair without medulla
2. Hair with medulla

Medulla can be absent, interrupted, continuous, and fragmental

Examination of Human Hair

A. Microscopic Examination
Before performing the examination take note of any foreign material on the hair and should be identified if
present in sufficient quantity. Hair should be cleaned with a mixture of equal parts of alcohol and ether.
1. Color.
 With the naked eye
 Under a microscope
Melanin. The brownish-black pigment in the hair, skin, etc. It is the chemical responsible for the color
of the hair. Black and brown hair differs only on the amount of melanin. Red is thought t be
due to iron.
2. Length. By actual measurement.
3. Character of the Hair. Whether wiry, stiff, or soft
4. Width Breath
5. Character of the Hair Tip if Present. Tip of the hair of the hair may shows whether a hair has been cut. Tips of body
hairs become rounded from rubbing against the cloth. Hair usually shows a fine tip. The tip of the hair of men is apt to
be cut-off square.
 Crushed tip/end Burned end/tip

(Evidence of singed hair has been of value in arson and firearm cases).
6. Manner by Which Hair had been Cut
 Cut with sharp tool (Clean and smooth)
 Cut by blunt/dull tool (The end severed cortial cells of the hair is rough).
 Cut for sometime
 Newly cut

7. Condition of Root or Base or Bulb of Hair

 Root of hair pulled forcibly (Have a portion of the sheath clinging to the root. Root is shaped like a bulb)
 Root of hair that has fallen naturally. (There is bulb formation at the root end. Has clean appearance
 with nothing adhering to it. Root is dry and small).

Two (2) Kinds of Hair Roots

1. Living roots. Often found on hair in full growth.
2. Dry roots. Dead roots of hair

The hair root does not give much information as to the origin of the hair. Very often the root is missing on hair found on cloth at the
scene of the crime, on weapons, etc. The examination of the root will only give clue as to whether the hairs have been pulled away by
force or have fallen out spontaneously and there are three (3) possibilities:
1. All hairs have living roots. In case they have not fallen out themselves but have been pulled away by force.
2. All hairs have dry roots. In this case, they have most certainly fallen out themselves.
3. Some hairs have living and some dry roots. In this case, they have been pulled away by force, the living hairs with dry ones.

8. Character of Cuticle.
The size, general shape, and the irregularity of the scales are observed.

9. Character of Cortex
Structural features are studied under the microscope. Cortex is embedded with pigment granules that impart hair with
color. It is the color, shape and distribution of these granules that provides the criminalist with important points of comparison
between the hairs of different individuals.

10. Presence of Dye in Hair

Dyed hair can be distinguished from natural hair. Under the microscope, dyed hair has a dull appearance and the color
tone is constant, whereas natural hair is not and the individual pigment granules stand more sharply. If there has been subsequent
growth of the hair since dyeing, the undyed root end portion will standout markedly. Bleached hairs have a rough appearance, are
more uniform in a shade and contain less pigment depending on the amount of bleaching. Dye absorption and chemical tests have
been developed for the detection of bleached hair.

11. Determination of Whether Naturally or Artificially Curled

12. Character of Medulla

B. DNA Examination
If the root of the hair strand is intact, a DNA test can be performed.

Medulla
The medulla and cortex are the most characteristic portion of the hair. Have more distinguishing quantities, thus cortex and
medulla yield the most reliable criteria in the diagnosis of hair.
Cuticle

Medulla

Cortex
 Longitudinal Cross Section of a Hair
Medulla or core or central canal of the hair can be continuous or interrupted. It is continuous in large animals, very often
interrupted in human, monkey, and horses.

The diameter of medulla can be absolutely constant. At times alternately narrow and broader. The diameter of the medulla is of
very little importance but the relationship between the diameter of the medulla and the diameter of the whole hair is the great
importance.

Medullary Index (M, I.). Is the relationship between the diameter of the medulla and the diameter of the whole hair. Usually
expressed in fraction. Its determination is performed under a microscope provided with a micrometer eyepiece.

1. Hair with narrow medulla (less than 0.5 micron) belongs to human and certain monkey hair.
2. Hair with medium medulla (approximately 0.5 micron) belongs to hair of cow, horse and others.
3. Hair with thick medulla (greater than 0.5 micron) almost all animals belong to this.

Based on the medulla examination it can be determined whether hair is human or animal origin. The medulla is usually
narrower in width in human hair when present. Has finer and more numerous cross striations. Animal hairs usually consist of both
heavy guard hair and finer fur hair whereas human hair does not.
A comparison of the medullary index of the hair from the different parts of the body between man and woman is given in the table
below:
Body Parts Man (Micron) Woman (Micron)

Neck 0.115 0.163

Forehead 0.132 0.148

Eyebrows 0.236 0.233

Eyelashes 0.095 0.146

Beard 0.260 -

Genitals 0.153 0.114

Armpits 0.102 0.179

Comparison between Human and Animal Hair:

Human Animal

1. Medullary index is less than 0.5 micron. 1. Medullary index is more than 0.5 micron.

2. Medulla may not be present. 2. Medulla always present.

3. Scale pattern is fine and each one overlaps the other 3. Scale is coarse and overlaps less than ½.

more than 4/5.

4. Pigment granules are fine. 4. Pigment granules are coarse.

Collection, Packing, Preservation and Transportation of Hair

1. All of the hair in the questioned specimens should be submitted but do not mix hairs at different places.
2. In vicious assault and murder cases, obtain the clothing of the victim from the hospital or morgue to avoid the loss of evidence by
careless handling and to prevent the clothing from being destroyed.
3. Representative samples of hair from the victim as well as the suspect should be obtained if possible. To be a representative, head
hair samples from a particular individual it should consist of at least a dozen hairs from different areas of the scalp preferably full-
length hair.
4. Do not mix known samples of hair from different parts of the body.
5. The hairs should be placed in a folded paper or in a white mailing envelope, but the corners of the envelope should be sealed with
scotch tape.
6. Do not secure the hair samples to a piece of paper with scotch tape because this will damage the hair.
7. All foreign fibrous debris should be removed from the submitted specimen.
8. Fragmentary hairs or underdeveloped hairs are not suitable for examination.
9. Areas on an object containing hairs should be protected with cellophane or paper taped over the area before wrapping the object
from transmittal to laboratory.

Textile Fibers
A material mainly made from natural or synthetic sources. These materials will be converted into the making of textile yarns and
fabrics; woven, knitted, nonwoven and carpets.

Classification of Textile Fiber

The essential
or primary
properties of a textile fiber include:
1. High Length to Width Ratio:
For any fiber to be spun made to yarn and then into fabrics is that their lengths must be more than their widths. The minimum length
to width to ratio is 100:1.

2. Tenacity:
Referred to as the strength of the textile fiber. It is the force required to break the fiber. The strength is basically classified into three
(3) types on the basis of force direction of force:
 Tensile strength (Uniaxial Force)
 Tear strength (Biaxial Force)
 Bursting strength (Multi-axial Force).

3. Flexibility:
It is regarded as how much flexible or pliable a fiber is in order for it to be made into yarns and thereafter into the fabric for easy
movement.

4. Spinning Quality or Cohesiveness:

Cohesiveness is the property of the fibers to adhere to each other during the yarn manufacturing process. The process of spinning
makes the fiber surface resistant to friction and it is this lack of mobility that enables the fiber to stick together when being spun into
yarns.

5. Uniformity:
It is an important property of fibers because it is even yarns that make fabric uniform in appearance and consistent performance. It is
also associated with strength and other properties such as uniformity in length and thickness.

Importance of Textile Fiber as Evidence

In such incidences as homicides, assault and sexual offenses involving personal contact and struggle, textile fibers can be
inadvertently transferred between the clothing of a suspect and victim. Fiber transfers can also occur between people and their
environment (e.g., carpeting, upholstery or bedding). A force of impact such as in the case of hit-and run, the contact between the
victim and the vehicle may results to fabric impressions, fibers, threads or pieces of clothing left on the vehicle. An intruder entering a
broken window may leave fibers on the jagged glass or screen edges.

Collection of Textile Fiber Evidence

Fibers from the clothing of victim may still be on the suspect for quite some time after an incident. Submit the entire item to be
examined. If attempting to collect fiber evidence in the field, do not use alternate light since many fibers will not fluoresce under this
type of light and could be missed. If the entire item cannot be, tape lifts the fiber from the source and place in clean plastic surfaces for
transport. Do not place tape lifts on paper or cards as this may pose problem during recovery and comparison.

Fiber standards must be collected from known samples. All possible items from which the victim and suspect could have
obtained fiber transfer must be used as fiber standard. Do not attempt to remove questioned fiber from clothing unless absolutely
necessary to prevent loss. Submit the entire item in a sealed paper bag.

Important Reminders:
1. Fiber evidence are generally small in nature and thus must be protected from potential loss.
2. Due to their microscopic nature, several methods must be resorted to in order to ensure thorough collection such as: use of
magnification tools, and efficient alternative light sources.
3. Use recovery techniques that are least intrusive but practical such as picking, scraping and vacuuming.
4. Wrap pieces of evidence to protect any adhering fibers from being lost.
5. Collect comparison standards from possible sources of fiber transfer.
6. All items must be sealed and labelled for identification.

Test for Textile Fibers

1. Burning or Ignition Test
2. Fluorescent Test
3. Microscopic Test
4. Chemical Analysis
 4.1 Staining Test
 4.2 Dissolution Test

1. Burning or Ignition Test. A preliminary macroscopic examination. A test that determines whether fiber is mineral, animal, of
vegetable fiber.
Procedure: A single fiber is applied with flame at one end and the following are noted:
 Manner of burning
 Odor of fumes
 Appearance of burnt end
 Color of ash
 Action of fumes on moisten red and blue litmus paper.
 Effect of litmus on a piece of filter paper moistened with lead acetate.

For Animal Fiber: The fibers smoulder, or burn slowly and give odor like that of burning feather. When removed from the flame
they do not continue to burn readily and a charred bead remains at the end of the fiber. Fumes turn red litmus paper blue.
 Wool. Odor strong, disagreeable; fumes turn lead acetate paper black or brown.
 Silk. Odor not so pungent; fumes have no effect on lead acetate paper.
For Vegetable Fibers. The fibers burn rapidly with a flame and give off but little smoke or fumes. Charred
bead not present when fiber is removed from the flame. Fume turn blue litmus paper red.

2. Fluorescent Test. Used frequently to determine the general group to which the fiber belongs. It is not reliable for positive
identification of fibers. In general, the vegetable fibers exhibit a yellow in ultra-violet light, fluorescence whereas the animal
fibers show bluish fluoresecence.
3. Table below shows the Fluorescence of some common Fibers as obtained by Noptisch:
Material Color under Ultraviolet Daylight Color

1. Unbleached Wool Brilliant light blue Light yellow

2. Bleached Wool Bluish white to bluish yellow White

3 Bleached Cotton Light-yellow White

4, Mercerized Cotton Light-yellow White

5. Bleached Linen Brilliant yellowish-white White

6. Cuprate Silk. Reddish white with blue-violet shadow Brownish-white

7. Viscose Silk Sulfur yellow with blue shadow Brownish-white

8. Nitro Silk Brilliant flesh yellow Yellowish

9. Acetate Silk Bluish violet White

10. Natural Silk Very bright light blue, much brighter and White
whiter than acetate silk

4. Microscopic Examination. In general, it is the most reliable and best means of identifying fiber. The fiber is placed on a glass
slide, teased and covered with cover slip and identify the type of fiber seen under a microscope. Below is a table summarizing the
characteristics of some textile fibers:
Type of Fiber Appearance

Wool With overlapping scales throughout the cuticle.

Mohair Extremely similar in appearance to that of wool but bigger diameter and higher density; lustrous.

Cotton Flat, ribbon-like, twisted spirally on its axis, thick cell wall, covered by a thin waxy cuticle, fiber tapers
gradually to a blunt or rounded point at one end.

Silk Smooth, cylindrical, lustrous, usually single but often double very fine longitudinal striations with
infrequent cross-markings; more or less transparent.

Linen Straight and cylindrical, not twisted and flattened, tapering to a sharp point, cell wall, thick, lumen
appearing as a narrow dark line in the center of the fiber, fiber appears jointed, resembling bamboo, cross
lines frequently appearing like the letter X.

Comparison of Textile Fibers

4. Chemical Analysis of Fibers. The sample submitted for analysis is fairly large, such as a piece of cloth or a number of large
threads, it is suggested that chemical analysis be made to supplement the microscopic examination and confirm the results obtained
from that procedure.
 Staining Test. Fibers will react differently when stained using chemical reagents. The table below summarizes the behavior of
different types of fiber using the staining process.
Material Reagent Reaction
 Silk Picric Acid Dyed

Wool Picric Acid Dyed

Cellulose Fiber Picric Acid Undyed

Silk Millon’s Reagent Brown

Cellulose Fiber Millon’s Reagent Undyed

Cellulose Stannic Chloride Black

 Dssolution Test. This test is conducted by treating the fiber with certain chemicals. Fibers behave differently in the presence of
certain chemicals. Particular fibers may be dissolved while others will not dissolve. This can be used as a basis to identify types of
fiber.

The table below summarizes the behavior of different types of fiber using solubility test.
Fiber Name 59.5% Sulfuric acid, 20oC, 20 70% Sulfuric acid, 38oC, 20 5% Sodium hypochlorite, 20oC,
minutes minutes 20 minutes

Cotton Not Soluble Soluble Not Soluble

Wool Not Soluble Not Soluble Soluble

Silk Soluble Soluble Soluble

Rayon Soluble Soluble Not Soluble