Which category would include fibers that could tie a suspect to a scene?

• A. Chemical evidence
• B. Trace evidence
• C. Biological evidence
• D. Firearm evidence

Answer: (B)

Fibers are a form of trace evidence. They are small, easily transferred materials that can move between a person, their clothing, and a scene during contact, making them useful for linking a suspect to a location or event when fibers at the scene match fibers from the suspect’s clothing or belongings. In crime scene work, trace evidence involves tiny amounts of material that require careful collection and specialized analysis, such as microscopy and fiber comparison, to determine if the fibers originate from the same source. While the evidence is powerful for suggesting an association, it is typically class-level rather than uniquely identifying an individual unless there are distinguishing, source-specific features.

Locard’s exchange principle—the idea that contact leaves a trace on both the person and the object—underpins why fibers matter here. Other categories involve different types of material: chemical evidence covers residues like drugs or accelerants, biological evidence covers living material such as blood or saliva, and firearm evidence pertains to weapons, bullets, or tool marks. None of those are the fiber type being described.