At a crime scene, investigators are trained to recognize and distinguish what is or what
is not evidence. Anything, including the smallest glass fragment, single strand of hair, or
bloodstained brass statue, which could possibly lead to a suspect, is considered as evidence.
Investigators’ skill level and degree of concrete experience enables them to know what to look
for, where to search and how it should be carried out. Serious repercussions would result if any
substance or material questionable were discounted. (Saferstein, 2004).
Careful as a criminal may be not to leave evidence behind; miniscule particles of
materials are usually transferred unknowingly to or from a victim or scene. This is precisely the
type of connection, between victim and suspect, investigators are looking to find. These tiny bits
of physical material, that can be transferred from person to person, are known as
and vital to a case.
Two types of trace evidence are soil and glass. Both are classified as class rather than
individual evidence, as they usually can only be linked to a common source, not to one
individual, and primarily supplement other evidence, rather than stand on their own. More often
than not, trace evidence excludes a suspect, as it typically cannot be tied to any one specific
person or place, with absolutely certainty.
Glass as evidence
Due to the variability and quantity of items made from glass, it is extremely critical to
perform a thorough search and collection for glass fragments. More often than not, examiners
are trying to determine the probability that two pieces are alike, or came from a common source.
The chemical composition of glass from a car’s windshield, headlights, windowpanes, or
a drinking glass are all different and can be distinguished through an examiner’s analysis. When
most glass breaks, it shatters and typically scatters pieces around a crime scene. For example,
the small glass fragments, from a broken window, may unknowingly attach to clothing, or lodge
in the shoes or hair of the person who committed the crime. (Lyle, 2004). The same goes for
Glass and Soil