READ: Glass and Soil Evidence

Introduction

 Evidence found at crime scenes is found in all shapes and sizes. Whether it is a fingerprint, a blood spatter, glass fragment or pair of muddy boots, a Forensic Investigator must understand the value of the evidence and how to collect and preserve it for analysis in the lab. Two substances most commonly examined by forensic scientists for their physical properties in a crime lab are glass and soil. Both are so common that the forensic scientist must determine properties that distinguish characteristics in an effort to find a unique identity that matches the evidence to the victim, the crime scene, or the perpetrator.

Essential Questions

1. What are the various types of evidence and how do they differ?

2. What types of crimes involve glass and soil?

3. In what ways do glass and soil evidence aid in solving a crime?

4. How are glass and soil evidence collected and preserved?

Module Minute

Evidence can make or break a case in court, so it is very important that a Forensic Investigator follow proper evidence collection procedure. If proper procedure for collection of evidence or chain of custody is not maintained, the evidence may be considered as tampered and inadmissible to court. Not all evidence has the same probative value, or value in court. Some types of evidence can be traced to a single source or person and are considered individual evidence, whereas other evidence known as class evidence is more general in nature. Individual evidence is preferred, but class evidence can also be used with mathematical probability to place a suspect or source at the scene of the crime. Glass and soil are two types of physical evidence that are commonly found in crime scenes and can tell an investigator many things including the geological features of a crime scene when the body has been moved, how an intruder entered a residence, and from which direction a bullet was fired.

Georgia Virtual, Forensic Properties of Glass and Soil Evidence, CC BY-NC-SA 3.0