Fiber Examinations

Fibers are all around us

Textile/Fiber Evidence Clothing Clothing Home Furnishings Home Furnishings Any Textile Product Any Textile Product Vehicle interiors Vehicle interiors Carpeting Carpeting Rope composition Rope composition Sporting goods/tires Sporting goods/tires Geo Textiles Geo Textiles Medical dressing Medical dressing

Fiber – the Fundamental Unit of Textiles /varying in length and composition

Fibers as Physical Evidence Fibers are among the most common type of physical evidence Fibers are among the most common type of physical evidence Large numbers can be shred from one surface and transferred to another surface. Large numbers can be shred from one surface and transferred to another surface. Fibers can often adhere strongly to a surface depending on a number of conditions Fibers can often adhere strongly to a surface depending on a number of conditions

Fiber Types Natural– found in nature – cotton, wool, silk Natural– found in nature – cotton, wool, silk Synthetic – manufactured – polyester, nylon, acrylic Synthetic – manufactured – polyester, nylon, acrylic

Examination Methods Macroscopic Exam Macroscopic Exam Microscopic Exam Microscopic Exam Micro Comparison Micro Comparison Color Analysis Color Analysis Microspectrophotometry Microspectrophotometry Composition Analysis Composition Analysis FT-IR FT-IR

Macroscopic Exam – Stereo Scope Examined under low power (7X) – while in the druggist fold

Microscopic Examination Compound Microscope 40X 200x

Fiber Characteristics Visual Appearance Length Color: natural/printed/dyed Cross Section/diameter Luster

Cross Section

Identification of Natural Fibers At the microscope

Cotton Comparison of red cotton Ribbon-like

Natural Fibers Natural fibers can only be identified by microscopic examination Natural fibers can only be identified by microscopic examination Physical properties cannot be changed Physical properties cannot be changed Often difficult to dye Often difficult to dye Instrumental analysis of natural fibers will only identify a cellulose (plant fibers) or a protein (animal hairs or silk) Instrumental analysis of natural fibers will only identify a cellulose (plant fibers) or a protein (animal hairs or silk) Cotton is most common Cotton is most common ex. White undergarments/denim jeans

Manufactured Fibers Any physical property can be manipulated in the production process Any physical property can be manipulated in the production process Color, size, length or morphology Color, size, length or morphology Composed of polymers Composed of polymers Identified by Chemical properties Identified by Chemical properties FT-IR or Polarized light FT-IR or Polarized light Stamford case Stamford case

Identification of Manufacturer Fibers FT-IR analysis

Microspectrophotometry Color - analysis

Fabric Examinations

FABRIC A planar structure made from the interlacing, looping, matting or fusing of yarns, fibers or filaments

WEAVE A fabric produced by the interlacing at 90° of two sets of yarns or filaments. A fabric produced by the interlacing at 90° of two sets of yarns or filaments. “STRENGTH” “CRISP” “DRESS SHIRT” NO STRETCH

KNIT A fabric produced by the interlooping of one or more yarns or filaments. “STRETCH” “RUN” T-SHIRT

NON WOVEN A fabric produced by the matting or fusing of fibers or filaments. A fabric produced by the matting or fusing of fibers or filaments. COMBINATION FABRIC A fabric produced by a combination of weaving and knitting or another process. (FELT/ WIPES)

Fabric Examinations Cut vs. Torn Cut vs. Torn Common Evidence in Sexual Assault Cases Common Evidence in Sexual Assault Cases Can corroborate or refute a story Can corroborate or refute a story Weave vs. Knit (Strength) Weave vs. Knit (Strength)

CUT vs. TORN CUT Often found at the bias “CLEAN EDGES” at damage Threads appear “blunt” TORN Damage at weakest area “RANDOM DAMAGE” Threads appear: “ragged/feathery/unraveled”

Examination Methods Macroscopic Examination Macroscopic Examination Microscopic Examination Microscopic Examination

Cordage Examinations Found as a binding on victims Smuggling cases Marine accidents Often found “around the house”

Cordage: A term for threads, yarns or rope produced by the twisting and/or braiding of fibers, plies or filaments.

Cordage Construction

Cordage Evidence Found as a binding on victims Found as a binding on victims Smuggling cases Smuggling cases Marine accidents Marine accidents Often found “around the house” Often found “around the house”