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Lesson 3-4: Forensic Awareness – Trace Evidence, Tool Marks and Impressions

Category
Training Material
Subject
Policing

Description

Material for a 2-hour lesson, part of the Criminal Investigation Course, developed by the Kosovo Police Service School

Subject
Policing
Target group
Cadets
Region
South-Eastern Europe
Keywords
basic police training, forensics, evidence, traces

Summary

As in the other ‘forensic awareness’ lessons, this lesson will focus on the unique skills of the KPS Forensic Technicians and the Forensic Laboratory staff. One of the most common types of physical evidence that the Investigators and Investigating Judge will encounter will be trace evidence. Trace evidence is a generic term for small, often microscopic material. Trace evidence at a crime scene can include such obvious things as blood, hair, glass particles, or paint. Trace evidence can also include less obvious, or less thought of items such as minute fibers, or even soil. In this lesson, we are going to discuss the general properties of hair, fibers, glass, paint, and soil and look at the value of each as evidence, and how to collect each of them properly. In addition, we will look at toolmark evidence. Investigators must not only be aware of the nature of this evidence, but also be familiar with the evidential value and proper methods of collecting it for subsequent comparison purposes. Finally, we will look at shoe prints and tire impression evidence as another form of valuable physical evidence that is often encountered at crime scenes. Since criminals must either walk or drive to and/or from the crime scene, it should be reasonably assumed that traces of impression evidence will be left behind. The recognition, collection, and examination of this impression evidence can provide irrefutable proof of the presence of an individual or a vehicle at a crime scene or in contact with a victim.

The purpose of this lesson is to introduce the participants to a variety of forensic evidence that can be found at a crime scene by the Forensic Technician. Officers will consider the properties of hair, fibers, glass, paint, soil, and toolmarks, as well as shoe and tire impressions. They will also look at where these items are routinely found, their evidentiary value in the investigation of a crime, and how they are collected as evidence and comparison standards.

At the end of this lesson students will be able to:

  1. Identify the evidential value of hair and fibres and the methods used to collect them.
  2. Describe the physical properties and evidential value of paint and glass.
  3. State the evidential value of rock or soil samples in a criminal investigation.
  4. List the four (4) ways in which toolmarks are made and where they might be found at a crime scene.
  5. Define the difference between two-dimensional and three-dimensional shoe and tire impressions, as well as the areas of the crime scene where they might be found.

Information

Added on
15 Jun 2003
Origin
OSCE Mission in Kosovo
Target group
Cadets
Region
OSCE Mission in Kosovo, Serbia
Keywords
basic police training, forensics, evidence, traces
Rights
OSCE