Why are fibers important in forensics?

Why are fibers important in forensics?

Hair and fibre are two of the most important resources in Forensic Science and are often responsible for providing valuable clues as to the identity of an assailant or attacker. Fibres too are an important discovery and can go some way to determining what an attacker or killer was wearing at the time of the incident.

What can fiber evidence tell us?

Like hair, fibers are considered class evidence. Fibers have probative value because they can create connections, or associations. Investigators compare physical and chemical characteristics of suspect (questioned) and known fibers. The more properties that are found to be similar, the stronger the case.

How are fibers analyzed from a crime scene?

The most common method uses microscopes to examine longitudinal and cross-sectional samples of the fibers. Forensic scientists prefer Scanning Electron Microscopy and Atomic Force Microscopy, which use a beam of electrons or the movement of a microscopic probe, over light microscopy due to the higher resolution.

How is fiber analysis used in forensic science?

Fiber analysis is also used by law enforcement agencies to place suspects at the scene of the crime. Transfer of fiber can occur during close contact with the victim or suspect. The most common use of fiber analysis is microscopic examination of both longitudinal and cross sectional samples.

How can hair and fiber be useful in an investigation?

In a criminal investigation, finding biological evidence such as hair proves helpful in establishing the scope of the crime scene, connecting a suspect to a weapon or the crime scene, supporting witness statements, or even connecting different crime scene areas.

What is the main purpose of fiber evidence in an investigation?

As such, fiber evidence is considered circumstantial evidence and strengthens any additional circumstantial or solid evidence against a suspect. When two objects come in contact during the commission of a crime there is transfer of material from one individual to another.

Why is fiber evidence important in a crime investigation?

The transfer of hairs and fibers and their discovery as trace evidence can be critical in linking a suspect to a victim or to a crime scene. Regarding fiber evidence, it is significant because textile fibers can be exchanged between two individuals, between an individual and an object, and between two objects.

How can fibers help solve a crime?

By matching fibers at the scene of a crime to items belonging to a suspect, investigators are able to place individuals at a crime scene. A case cannot be solved with fiber evidence alone, but when coupled with additional evidence, fiber is influential in solving a case.

What are fibers in a crime scene?

As discussed previously, fibers are considered a form of trace evidence that can be transferred from the clothing of a suspect to the clothing of a victim during the commission of a crime. Fibers can also transfer from a fabric source such as a carpet, bed, or furniture at a crime scene.

How would the uncommon fibers help in an investigation?

Identifying rare or unusual fibers at a crime scene has increased in significance, as it may place a suspect at the scene of the crime. By matching fibers at the scene of a crime to items belonging to a suspect, investigators are able to place individuals at a crime scene.

How do hair and fibers solve crime problems?

Hairs found on a victim routinely point to a suspect and because DNA analysis can often be done, this provides a definitive identification of the perpetrator. Likewise, fibers obtained from victims clothes or in the area of the crime scene can guide investigators in the direction of a particular suspect.

How can fiber be used to solve a crime?

How to collect fiber evidence from a crime scene?

USE a pair of forceps and COLLECT an “unknown” piece of fiber evidence found on the “victim”. PLACE the piece of evidence on a clean piece of paper. FOLD the paper twice to avoid contaminating the evidence. PREPARE a wet-mount slide of the evidence by placing a drop of water on the slide.

What do you need to know about fiber evidence?

PLACE the fiber evidence on it very carefully and COVER the evidence with a cover slip. USE a microscope to make observations of the fiber evidence under low, medium, and high magnification. What does the fiber look like? Are there striations on it?

Why are hair and fiber evidence so important?

Inasmuch as hair and fiber evidence can play a role in most cases involving violent crime, serious consideration should be given to collecting it properly. Once the crime has been committed, little time remains before hair and fiber evidence will be lost or contaminated. The importance of securing the crime scene cannot be overstated.

When is a questioned fiber compared to a known fabric?

When a questioned fiber is compared to fibers from a known fabric source, a determination is made as to whether this fiber could have originated from the known fabric.