Transcript Fibers Mr. McNiff CHS Forensics Introduction • Fragments of cloth can have individual and or class characteristics. • A fabric source can be verified when a portion of the.

Fibers
Mr. McNiff
CHS
Forensics
Introduction
• Fragments of cloth can have
individual and or class
characteristics.
• A fabric source can be verified when
a portion of the material can be
fitted physically with another piece
of cloth.
Introduction
• Fibers can be transferred by simple
contact between two objects.
• Fibers can be found at points of
entry, on rugs, couches, clothing,
hats.
• Cloth is comprised of small threads
which are composed of textile
fibers.
FIBER TRANSFER
• When fibers are transferred from
the fabric of an individual's clothing
to the clothing of another individual,
it is called a primary transfer.
• As these same fibers are
transferred to other objects during
subsequent contacts, secondary
transfers are occurring.
Fiber Number
• The number of fibers on the clothing
of a victim identified as matching
the clothing of a suspect is
important in determining actual
contact.
• The greater the number of fibers,
the more likely that contact actually
occurred between these individuals.
Fiber Location
• Where fibers are found also affects
the value placed on a particular
fiber association.
• The location of fibers on different
areas of the body or on specific
items at the crime scene influences
the significance of the fiber
association.
Fiber types
• Fibers can be classified as
–Mineral (glass, asbestos)
–Animals (silk, wool, fur)
–Vegetable (cotton, linen, hemp)
–Synthetic (rayon, nylon, dacron,
acetate)
Fiberglass
Asbestos
Silk
Wool
Fur
Cotton
Linen
Hemp
rayon
nylon
dacron
acetate
Synthetic fibers
(a) Acetate fiber. (d) Orlon fiber.
(b) Nylon fiber.
(e) Dacron fiber.
(c) Rayon fiber.
Chemical analysis
• Burn test– burning fiber may give
off a particular odor and leave a
residue which is brittle, ash like, or
a hard bead.
• Solvent/solubility test- determine if
a fiber will dissolve in acetone, HCL,
Sodium Hypochlorite.
Chemical analysis
• Stain test- checks to see if a
particular stain will adhere to the
fabric/fiber
• Microscopic examination- the
quickest, most accurate, and least
destructive means of determining
the microscopic characteristics of
textile fibers.
microscope
• Should be used first to examine
fibers.
• Physical features such as
–Crimp
–Length
–Color
microscope
–Relative diameter
–Luster
–Apparent cross section
–Damage
–Adhering debris should be noted.
Pictures
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http://www2.fbi.gov/hq/lab/fsc/backissu/july2000/deedric3.htm
http://www.fantom-xp.com/wp_12_~_Hair_Neon.html
http://www.maine.gov/dps/msp/criminal_investigation/crimelab/phymatch.
htm
http://www. seedol.com
http://www. volpeenterprises.com
http://www. cakehead.com
http://www. topnews.in
http://www. whitecloud.co.uk
http://www. kaneva.com
http://www. eoa-co.com
http://www. alpinemeadowsguild.org
http://www. linenkids.com/page.html?id=15
http://www. hemptraders.com
http://www. whyfiles.org
Pictures
• http://www. ecouterre.com
• http://www. ccmr.cornell.edu
• http://www. source4style.com
• http://www. micro.magnet.fsu.edu
• http://www. home.gci.net
• http://www. ymccoll.com
• http://www. scienceclarified.com
• http://www. sciencephoto.com
• http://www. accessscience.com
• http://www. labgallery.com
• http://www. spsj.or.jp
• http://www. tbc.school.nz
Reference
• Sutton, James V. Forensics: the Search for Clues. West Chester, OH:
Kemtec Educational Corporation, 1997. Print.
• Deedrick, Douglas W. "Deedrick - Forensic Science Communications - January
2004." FBI — Federal Bureau of Investigation. FBI — Federal Bureau of
Investigation, Nov. 2004. Web. 23 Aug. 2011.
<http://www2.fbi.gov/hq/lab/fsc/backissu/jan2004/research/2004_01_resear
ch01b.htm>.