chapter  Chapter 14
44 Pages

Materials evidence

WithHoward A. Harris, Henry C. Lee

This chapter discusses the term "trace evidence"—paint chips, glass fragments, hair, fibers, soil, and many other materials. Materials evidence is often used to establish or disprove contact connections between objects. It becomes particularly important when it is transferred. In almost all forensic laboratories, the two most common sources of transferred materials evidence are clothing and vehicles. Techniques for collection of materials evidence include picking off the material with forceps, tape lifting, mechanical dislocation of surface materials, and vacuuming. One of the most important developments for the analysis of materials evidence since the development of the microscope itself was the perfection of the microscope attachment for a Fourier transform infrared spectrometer. Successful laboratory examination of materials evidence, including fibers, depends upon the collection of proper control samples. Most forensic laboratories would list paint as one of the three or four most commonly encountered types of materials evidence, probably right after the top two, hairs and fibers.