Fiber: Protocols for Examination

Protocols for the examination of fibers need to start at the crime scene as the value of fiber examinations is often reduced, or indeed negated, when the crime scene examiner fails to take appropriate action to protect and/or recover items, which may yield fiber evidence. The recovery of potential fiber evidence needs to be managed in the context of an investigation and in a holistic manner paying due attention to all forms of physical evidence. However if fibers are to be examined, active steps need to be taken to recover them at the earliest opportunity and approaches in the field and laboratory need to minimize the potential for loss of fibers and/or compromise through contamination. Once in the laboratory, protocols should consider methods for the efficient and effective recovery of fibers aimed at facilitating subsequent examinations. Microscopic examinations play a central role in fiber examination. Protocols need to emphasize the need to look for differences between recovered/questioned fibers and fibers from known sources. Hence, techniques need to have a cascading and increasing ability to discriminate, accepting that some techniques have complimentary value. Fiber examination is essentially a comparative process and the comparison microscope plays an essential role.Techniques such as Fourier transform infrared spectroscopy, microspectrophotometry, Raman spectroscopy, and mass spectrometry provide useful information on fiber identification and/or color or dye components.