Forensic Science - 03 Fibres and fabrics

DRYSDALE CSI
Fibres and fabrics.
Ian Anderson
Saint Ignatius College Geelong

 When we wear clothes, walk on carpet, sit on the
lounge or pull on a jumper, fibres either fall off or
are picked up.
WHY FIBRES?
Source: http://blog.stylewithcindy.com.au/boxing-day-sales-tips/

 Fibres are used in forensic science to create a link
between crime and suspect.
 Fibres are a form of trace evidence.
 Direct transfer = fibres are transferred directly from
victim to suspect or from suspect to victim.
 Secondary transfer = the victim has picked up fibres and
then transferred them to the suspect.
 Most common form of fibre transfer is shedding of
textile.
 e.g. clothing, carpets and upholstery.
WHY FIBRES?

 Forensic scientists will try to
determine
 The type of a fibre.
 It’s colour.
 How many fibres of each kind were
found.
 Where they were found.
 What textile the fibre came from.
 Whether there were transfers of
multiple types of fibres.
HOW FORENSIC SCIENTISTS USE FIBRES.
Source: http://www.exploreforensics.co.uk

 The value of fibre evidence is dependent upon its
potential uniqueness.
HOW FORENSIC SCIENTISTS USE FIBRES.
Source: http://www.tumblr.com/tagged/pink%20everything

 Fibres are classified as either natural or synthetic.
FIBRE CLASSIFICATION.
Source: http://www.modernhometoday.com/natural-vs-synthetic-furniture-fabric-
advantages-disadvantages/

NATURAL FIBRES.
Come from animals, plants
and minerals mined from the
ground.
 Animal fibres.
 Hair (e.g. wool, cashmere,
mohair, angora).
 Fur (e.g. sheep, fox).
 Silk.
Source:
http://martybugs.net/gallery/?gal=200712Busselton
&img=IMG_11013

NATURAL FIBRES.
 Plant fibres.
 Seed fibres (e.g. cotton).
 Fruit fibres (e.g. coir from
coconuts).
 Stem fibres (e.g. hemp, jute
and flax).
 Flax = linen.
 Leaf fibres (e.g. sisal and
manila).
 Mineral fibres.
 e.g. fibreglass and asbestos.
Source: http://cottonaustralia.com.au/cotton-
library/video

SYNTHETIC FIBRES.
 Categorized as polymers and regenerated fibres.
 Over half of fibres produced today are synthetic
fibres.
 Synthetic polymer fibres.
 Petroleum products.
 Include polyester, nylon and acrylic.
 Regenerated fibres.
 Are mostly plant in origin and
are derived from cellulose.
 Include rayon.
Source: http://www.funkyflytying.co.uk

 Synthetic fibres are stronger than the strongest
natural fibres!
 Unlike natural fibres, synthetic fibres are not
damaged by microorganisms.
 Synthetic fibres melt at a lower temperatures
compared to natural fibres.
 Unlike natural fibres, synthetic fibres can be
damaged by sunlight
NATURAL V SYNTHETIC FIBRES

 Under the microscope.

 Under the microscope.
Source: http://luthvarian.blogspot.com.au

 Fibres too short in their raw
state to be used as textiles
may be spun together to make
yarns.
 For example, cotton fibres are
only up to 5cm in length and
must be spun together to form
a very strong yarn.
 Wool is also spun together to
make a yarn.
 Synthetic fibres can also be
spun into yarns.
YARNS
Source: Bertino 2012

 Fibres can be woven into
textiles or fabrics.
 There are many different types
of weave patterns.
 e.g. tabby, twill and satin.
 Textiles will also differ in their
thread count.
 e.g. bedsheets can be 180, 300
or 500 threads per inch.
TEXTILES
Plain weave Satin weave

CASE STUDY
Roger Payne (1968).
 Bernard Josephs arrived home to find
his wife dead. She had been wearing a
purplish-red (cerise) woollen dress. On
examination, it was determined that
Claire Josephs had been choked into
unconsciousness and then had her
throat cut with a serrated knife. There
was no forcible entry, and Claire
appeared to have been in the middle
of cooking. This indicated to the police
that the murderer was probably
someone Claire knew.

CASE STUDY
Roger Payne (1962).
 Suspicion fell to an acquaintance named Roger
Payne. On examination of his clothing, more than 60
of the unusual cerise coloured fibres were found.
These fibres led to the further examination of
Payne’s clothing, and fibres from a red scarf similar
to Payne’s were found under Claire’s thumbnail.
Additional evidence led to the conviction of Payne
and the sentence of life imprisonment.

CASE STUDY
Amanda Davies (1992).
A woman was found knifed to death under a bridge. She was wearing a blue-
and-gray acrylic sweater. There were no fingerprints, no witnesses, and no
weapon. She had recently returned from a vacation and had some
photographs of herself in some provocative poses with strange people. On
the night she died, she told her parents she was going to see her boyfriend
and show him the pictures to "rekindle his interest."
After the body was found, her boyfriend was interviewed. He said that he had
seen her and that she had been in his truck, but that he had dropped her off
"downtown." After obtaining a search warrant, investigators searched his truck
and found a yellow polyester blanket.
When the crime laboratory examined the sweater, they found about 40 yellow
polyester fibers similar to those from the blanket. Likewise, examination of the
blanket revealed more than 30 blue and gray acrylic fibers that matched the
sweater. No attempts were made to determine how readily the sweater or
blanket shed fibers or how well foreign fibers adhered to these textiles. It
would not have been proper to put the actual articles in contact with each
other, but the defense argued that similar garments could have been used to
investigate the "sheddability" of the garments.

CASE STUDY
Amanda Davies (1992).
At the trial the prosecutor tried to establish that there was a "primary transfer"
between the blanket and the sweater and that the large number of fibers
mutually transferred showed that the transfer had been recent. In other
words, the prosecutor argued that the blanket had been in direct contact with
the victim's sweater right before she died. Because the blanket was found in
the truck, this implied that she had been in the truck shortly before she died.
This was virtually the only physical evidence available during the case. The
other circumstances, such as those shown in the photographs, were used to
establish a motive.
The defense argued that the number of fibers transferred may or may not
indicate a primary transfer. If these garments shed easily, the victim could
have deposited fibers from her sweater into the suspect's truck on a previous
occasion. Because the accused kept the blanket in the truck at all times,
sometimes in the front seat, the defense argued that the sweater could have
picked up blanket fibers from the truck seat; in other words, the truck seat
could have acted as an intermediary for a secondary transfer of fibers.
Because the crime lab had not done any testing to determine how easily
these garments shed, the prosecutor could not know if the 30 to 40 fibers was
a "large number."
Faced with these arguments, the jury returned a verdict of "not guilty."

Bertino, A.J. (2012). Forensic Science: Fundamentals
and investigations. Melbourne: Cengage Learning.
BIBLIOGRAPHY.

http://sick9CSI.wikispaces.com

Forensic Science - 03 Fibres and fabrics

Recommended

Recommended

More Related Content

What's hot

What's hot (20)

Similar to Forensic Science - 03 Fibres and fabrics

Similar to Forensic Science - 03 Fibres and fabrics (18)

More from Ian Anderson

More from Ian Anderson (20)

Recently uploaded

Recently uploaded (20)

Forensic Science - 03 Fibres and fabrics