11 1 Common Weave Patterns of Textile Samples

Fibers in Forensic Science s Fibers are class evidence. s Fibers create a link

Fibers as Trace Evidence s Fibers may be transferred directly from victim to suspect

Secondary Transfer s If a victim has fibers on his person that he picked

Early Collection s 95% of fibers are lost within the first 24 hours of

Type of Fibers s What is the composition of the fiber? s Is it

Number of Fibers Found s How many fibers found? s More fibers suggest a

Multiple Fiber Transfer s Are there more than one type of fibers? s Are

Type of Crime Committed s Each crime has an expected pattern of contact between

Time Between Crime and Discovery of Fiber s Unless fiber location is undisturbed the

Sampling Fibers s Fibers are gathered at crime scene. s Special vacuums s Sticky

Testing Fibers s First task is to identify fiber. s Clothing s Upholstery s

Testing Fibers With a Microscope s How light behaves when interacting with fibers can

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11. 1 Common Weave Patterns of Textile Samples Chapter 11: A Study of Fibers and Textiles November 30, 2014 Sanders 8: 36 PM

Fibers in Forensic Science s Fibers are class evidence. s Fibers create a link between the crime and the suspect. s As with hair, clothes shed fibers. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Fibers as Trace Evidence s Fibers may be transferred directly from victim to suspect of suspect to victim. s This is known as direct transfer. s As you can see fibers are in direct contact with victim. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Secondary Transfer s If a victim has fibers on his person that he picked up and then transferred to to a suspect, it is called secondary transfer. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Early Collection s 95% of fibers are lost within the first 24 hours of an incident. s Collect fibers after a thorough examination. s Only collect out-of-place fibers September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Type of Fibers s What is the composition of the fiber? s Is it rare? s Where are the fiber found in relation to the crime scene? s What was the color? September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Number of Fibers Found s How many fibers found? s More fibers suggest a violent encounter. s Where were the fibers found? s If they were near or on victim’s body, you can place the victim to the scene September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Multiple Fiber Transfer s Are there more than one type of fibers? s Are there numerous sources? s More variety of fibers suggest longer contact or more violent contact. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Type of Crime Committed s Each crime has an expected pattern of contact between s Suspect s Victim s Crime scene s This pattern is reflected in fiber transfer. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Time Between Crime and Discovery of Fiber s Unless fiber location is undisturbed the value of found fiber is greatly reduced with the passage of time because fibers will be expected to fall off. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Sampling Fibers s Fibers are gathered at crime scene. s Special vacuums s Sticky tape s Forceps s Important to notate and record where the fibers where gathered from. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Testing Fibers s First task is to identify fiber. s Clothing s Upholstery s Carpeting s Try to match fiber to its source. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM

Testing Fibers With a Microscope s How light behaves when interacting with fibers can help determine the fiber. s Polarizing light s Infrared light s Can determine chemical structure of fibers. September 3, 2021 Unit 5: The Study of Fibers and Textiles 8: 36 PM