(AHFBM) Types of Fibers Lesson

Types of Fibers

Locard's exchange principle states that materials are exchanged when two objects come in contact with each other. The exchange of fiber evidence can occur as the clothing of the victim and the suspect come in contact with each other as well as fibers at the crime scene. A textile is an artifact made by weaving, felting, knitting, or crocheting natural or synthetic fibers. Textiles can be initially categorized by their weave patterns. Further examination of the individual fibers would reveal the type of fiber, length, color, and method of spinning. Fibers can also be classified as natural or synthetic (man-made).

Natural Fibers

Natural fibers originate from plant and animal sources. They have been used throughout history in all climate regions to meet the needs of the people who lived there. Native plant and animal species were relied upon for fibers to create clothing, items for the home and even to manufacture tools! The most widespread plant fiber today is cotton. Because cotton is so common, its value as evidence is almost insignificant. Animals such as sheep, rabbits and goats account for some of the more common natural animals fibers. Wool is the most common animal fiber and is often used in the manufacturing of clothing and carpeting. Finding wool or cotton fibers at a crime scene would not be all that helpful unless the wool or cotton fibers had a distinctive characteristic or could be linked to a suspect in some way. Less common animal fibers such as Angora or Mohair could potentially be more helpful in an investigation simply because they are more rare. Finding a pale pink Mohair fiber is much more unusual than finding a gray wool fiber, for instance. Fiber evidence, as mentioned, is class evidence, so it requires careful analysis and corroborating evidence to be useful in a case. While fibers alone generally are not sufficient evidence for a judicial decision on a case, several types of class evidence can be compiled and a probability can be calculated which suggests a link to a specific suspect.

Interactivity: Natural Fibers

When observing natural fibers under a microscope, the fibers appear to be less uniform and to have rougher edges as compared to synthetic fibers.

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