Like violent crime, sexual battery concerns a very intimate encounter between two people. During such encounters, it is not uncommon for clothing to get torn, snagged, or ripped. When this occurs, pieces of the clothing’s fabric may be left behind at the crime scene or may be transferred from one person to another. In some sexual battery cases, it is not uncommon for pathological offenders to keep an article of the victim’s clothing as a memento of the attack.
Fiber Evidence
When any of these circumstances arise, it may help the prosecution to prove that the defendant had an article of the victim’s clothing or a fiber from the victim’s clothing in his/her possession. Conversely, it may help the prosecution to prove than article of the defendant’s clothing or a fiber from the defendant’s clothing was present at the crime scene.
Fiber evidence can be valuable to both prosecutors and criminal defense lawyers alike. On the one hand, it may help prosecutors prove that the defendant was present at an incriminating place. On the other, it may help criminal defense lawyers challenge the prosecution’s case when fiber evidence doesn’t match the defendant or fails to be linked to the defendant in any way.
In cases like these, identification may be an issue. In other words, if the attack was committed by one stranger on another, the prosecution may be charging the wrong person. Of course, the strength or weakness of such a defense will depend on the presence of other evidence in the case. Clearly if reliable DNA evidence proves the defendant has a sexual encounter with the alleged victim, it will be hard to challenge whether or not the defendant’s identity is at issue.
In another section, we will discuss the reliability issues that exist when victims of crime are asked to identify attackers they do not know personally or have never met before. As we will explain, the most common type of misidentification occurs when a victim of one race is asked to identify an attacker of a different race.
Regardless, when crime lab technicians compare two fibers, they look for the following characteristics, among others:
- Color
- Transparency
- Translucency
- Thickness
- Cross-sectional shape
- Natural fiber versus synthetic
- Curvature/coiling/straightness
Analyzing a sample fiber to see if it matches a fiber taken from a crime scene is not overly complicated. Unlike DNA analysis that involves a complex scientific process, fiber analysis amounts to nothing more than visually comparing one sample to another.
To understand how this analysis is conducted, one must first understand where fibers come from. As you may already know, natural fibers come from animals and plants. On the other hand, synthetic fibers are manufactured in factories. Synthetic fibers can be made in a seemingly infinite number of variations.
Some fibers are thick, others are thin. Some are opaque, others are transparent. Some fibers are translucent, others are clear.
When synthetic fibers are manufactured, they begin life as a melted liquid. During this process, dyes and other ingredients, such as glitter can be added. These other ingredients give the fiber color, shimmer, translucence, thickness, rigidity, texture, and other characteristics that effect their ultimate appearance.
Once the mixture is complete, the liquid fiber is then poured through a grate. As the fiber pours through the grate, strands of fiber form (almost like spaghetti). These strands get their shape from the little holes in the grate they pass through.
If one can imagine, a grate resembles a bug screen on a window. If you poured liquid plastic through the bug screen, the strands that form would take the shape of the little holes. It is this shape that gives synthetic fiber one of its main identifying characteristics. When a fiber is cut I half, its shape is revealed.
Some fibers are circular, others are star shaped, and some are rectangular. It all depends on what the fiber’s intended use was.