The different types of fibers like animal fiber, synthetic fiber, vegetable fiber, mineral fiber and also both human and animal hair are encountered during investigation of crime since used in varied house hold materials and available on human/animal body parts. In one case, a textile consignment containing wearing apparel (sari) was seized at state border gate and imposed tax since appearing alike natural silk sari. The trader filed a complaint claiming the wearing apparel (sari) to be spun with synthetic fiber and requested to levy tax accordingly. The matter was not settled as such, one disputed sari was received for forensic examination to ascertain the nature of fiber (natural/synthetic) used to decide the tax on the textile consignment. The fibers used in the disputed sari were collected and compared with genuine silk conducting physical features, microscopic, scanning electron microscopic (SEM) and FTIR studies. The forensic examination ruled out the use of silk fiber in knitting the disputed sari and solved the case. The details have been discussed in this paper.
The demand of textile products has led to the invention and production of an increasing range of man-made/synthetic fibers. Presently total worldwide production of man-made fibers is on a par with natural fibers . The natural fibers such as silk, sinew, wool, animal hairs, flax, cotton, jute, bamboo etc. and the man-made synthetic fibers such as rayon, acetate, nylon, olefin, acrylic, polyester etc. are very commonly used in different wearing apparels. The fiber used in textile is the smallest single unit forming the basis of the textile yarn and the yarn is composed of numerous fibers which are twisted together to prepare the unit for weaving. This is commonly known as thread. Many times fiber is dyed for knitting. The dye is very much helpful as additional evidence for forensic comparison by TLC . Different types of cases are reported where examination of fiber is involved for forensic evidence [3-6]. They are:
I. Disputed wearing apparel to ascertain the origin of fiber
II. Disputed sock/blanket to ascertain the percentage of wool used
III. As trace evidence at crime scene like murder/rape/accident cases fiber analysis is helpful
IV. Distinguish between fiber and hair
V. Forensic examination of all types of fiber (animal, vegetable, mineral, hair, silk, polymer, rayon etc. are done in disputed cases)
VI. Examination of fiber help to link between victim, accused and scene of crime
VII. In hanging cases, fibers are collected from victim’s neck for examination/comparison with hanging material like rope etc.
VIII. Examination of animal fiber at crime scene is of great significance
IX. Two pieces of rope, cloth etc. are compared to establish the common origin to link evidence with suspect – crime scene
X. Examination of ornaments used along with fiber in costly garments may have immense forensic value
A trader was transporting textile consignment containing synthetic wearing apparel (sari) and the tax department imposed tax considering natural silk sari. There was huge
financial loss, as such the trader lodged legal complaint against
the tax department to levy tax for synthetic fiber product. As per
complaint, the disputed sari was sent for forensic examination
to ascertain the fiber used for knitting the sari. The forensic
examination was done and based on the report tax was collected
accordingly and the trader got relief from financial burden in
Standard sample of natural silk fiber was collected from
government department and fiber used in disputed sari was carefully isolated for different studies (Figures 1 & 2). In order
to observe both the silk fiber and the fibers used in sari under
microscope, a furrow was made on the paraffin block (cube)
using a hot scalpel. A few silk fibers and fibers used in sari were
taken and placed separately in the furrow. Thereafter, the gap
was filled with liquid paraffin and the whole block was allowed
to solidify in a refrigerator. The paraffin wax block so formed
used to obtain thin sections of fibers manually with the help of a
hand razor blade. The cut sections were de-waxed using xylene
and were placed on a slide for observation under microscope
(Leica DME, Germany) at a suitable magnification (100X-400X)
In this case textile consignment (sari) was seized to examine
the origin of fiber and levy tax accordingly. The forensic
examination/comparison of the fiber of the disputed sari along
with genuine silk fiber was conducted and the results found on
physical properties, microscopic, SEM and FTIR studies could
conclusively prove that the disputed sari was not spun with
natural silk fiber. The results of forensic examination could
establish the fact and settle the legal dispute in this case.
The authors are thankful to the Director, Sericulture Dept.,
Govt. of Tripura for providing genuine silk fiber for examination,
and also to Dr. S.K. Jain, Director, CFSL, Chandigarh, MHA, Govt.
of India and Mr. S.K. Chakraborty, Dy. Director, SFSL, Tripura for
conducting SEM and FTIR study respectively.
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