ABSTRACT
The term trace evidence refers to a very broad category of physical evidence. The trace evidence category covers a larger variety of physical evidence types than any other division [1-3]. A discussion of the attributes of physical evidence that make it trace evidence will follow in a later section of this chapter. Anything or any material can be physical evidence. This term has both a legal and a scientific meaning. In the legal context it refers to tangible objects that are brought into court and formally entered into evidence as exhibits (or productions). Obviously, such objects need not be entered into evidence in a legal proceeding to constitute physical evidence from the scientific point of view. Any objects and materials from a crime scene (or suspect, victim, etc.) that may shed light on an investigation are physical evidence from the scientific perspective. They become physical evidence as soon as they are recognised as having possible significance. The process of evidence recognition is more complex and challenging than is generally appreciated. It requires considerable scientific knowledge and skill as well as experience. Evidence recognition, both at the crime scene and in the laboratory, needs to receive more attention from scientists in cooperation with non-scientist investigators.
