What are challenges forensic scientists face in dealing with fiber evidence?

The thing about fiber evidence is that it becomes lost, very quickly. I'll assume that you already know what fiber evidence is. It's basically any sort of evidence that is thread-like, such as small threads of cotton, animal hair, or the tiny pieces of a carpet. Again, fibers fall away, and disperse, very quickly. After four hours, about 80% of potential fiber evidence is gone. After 24 hours, about 95% of potential fiber evidence is gone. The challenge here is to collect fiber evidence as soon as possible. Time is very crucial.

not only is obtaining the evidence problematic but also is getting to the source of fiber evidence. DNA evidence obtained from fiber evidence is often in small amounts. That is why we have processes like DNA Amplification. If you have a hair fiber it is challenging in that the dna can be destroyed by hair chemicals or it could be from a wig. Tracing the source, wig if so what is the chemical makeup of the fiber etc.