Chapter 4: A Study of Fibers + Textiles

• create a link between crime and suspect • trace evidence • locardś exchange principle • direct transfer • secondary transder > victim picked up the fibers and transferred them • early collection is important - 24hrs • only fibers you would not expect to find

• type • color • # of fibers • where the fiber is found • textile the fiber came from • multiple fiber transfers • type of crime committed • time between crime & discovery of the fiber

• vacuums • sticky tape • forceps • be accurate!

textile

• Identify the color/shape/type • Match it to fibers from the suspects source such as a car or house • One fiber • More than one

clothing, carpets & upholstery

weaving or intertwining yarns together

fibers that are spun together

natural and synthetic

plants, animals, and minerals mined from the ground

• cocoons of the caterpillar • shimmering appearance is caused by the triangular structure of the fiber. It scatters light • clothing and bedding • doesn´t easily shed

• neither protein or cellulose • ex. fiberglass > fibers are very short, weak and brittle. Used as insulation • asbestos > durable. Used in brake linings, ceiling tiles, floor tiles

• specialized plant cells • grouped from the part of the plant they come from • seeds, fruits, stems & leaves all produce plant fibers • all have diff. characteristics • most common is cotton • short > 2-5cm • become brittle over time • trace evidence

• can come from 3 sources: hair, fur and webbing • all are made of proteins • used in clothing, carpets, curtains & bedding

• made from cellulose and are mostly plant • ex. rayon - found in carpets

• made w/ petroleum products and are non cellulose based • totally man-made • textiles and ropes • strong • cannot be destroyed by microorganisms • deteriorate in bright light • melt at low temperatures

• most common • fleece & wrinkle resistant pants • can be added to natural fibers to provide strength

• similar to polyester • easily broken down by light & concentrated acid

• light and fluffy • clothing tends to ball or pill • inexpensive

• high performance • quick drying • resistant to wear

(man made fibers) - 1/2 of the fibers produced today are man made - there are 2 types of synthetic fibers

• can be destroyed by microorganisms • plants, animals, minerals

• man made or combination of natural and synthetic • durable

yarn - can be spun thick, thin, loose or tight - weave pattern is 1 way that fibers are diff.