Crime Scene Investigation Laboratory Manual

Marilyn T Miller

• Publisher: Academic Press
• Year: 2013
• ISBN:
  9780124058736
• Topic: Law
• Subtopic: Forensic Science
• Index: Law

Crime Scene Investigation Laboratory Manual provides information, examples, and exercises for all aspects of crime scene investigation. The exercises will teach the proper techniques for securing, documenting, and searching a crime scene, how to visualize or enhance the evidence found, how to package and preserve the evidence, and how to reconstruct what happened at the crime scene. This manual is intended to accompany any crime scene investigation textbook. Written by a former crime scene investigator and forensic scientist, the information is practical, straightforward, and will be immediately applicable. Learn all the latest techniques and procedures including deconstructing first responder contamination, the preliminary walk-through, utilizing associative evidence, enhancing trace, biological, and chemical evidence, and reconstructing scenes through wound dynamics, glass fracture patterns, bloodstain patterns, ballistics, and more.

• Designed to complement any text used in crime scene investigation courses
• Over 20+ proven exercises with material from actual crime scenes, providing students with hands-on learning
• Written by an experienced educator and former crime scene investigator/forensic scientist

Section IV

Physical Evidence at Crime Scenes

Outline

Exercise K Physical Searches

Exercise L Visualization and Enhancement: Lighting Aids

Exercise M Visualization and Enhancement: Biological Evidence

Exercise N Visualization and Enhancement: Chemical Evidence

Exercise O Visualization and Enhancement: Combination Methods

Exercise P Packaging, Preservation, and Collection of Evidence

Exercise K

Physical Searches

Exercises to illustrate the common physical searching techniques.

Outline

Objectives of a Crime Scene Search

General Concepts of Crime Scene Searches

Crime Scene Search Patterns

1. Link Method

2. Line (STRIP) Method

3. Grid Method

4. Zone Method

5. Wheel/Ray Method

6. Spiral Method

Laboratory Data Sheet

Discussion Questions

Objective

To practice geometric search patterns commonly used to intensively search at crime scenes.

Physical evidence obtained from the crime scene contributes greatly to the successful outcome of the case investigation. Although it is theoretically possible that a perfect crime has been committed with the perpetrator leaving minimal physical evidence, it is more likely that the critical evidence was never found. The other tasks performed at a crime scene can be learned, but the simple task of finding that critical evidence must never be the failed task of the crime scene investigation. The successful search for evidence will only occur when crime scene investigators understand the objectiveness of a crime scene search and rely on a systematic, structured search process.

Objectives of a Crime Scene Search

The goal of a crime scene search is to locate all potentially relevant and meaningful physical evidence that could be used to link or exonerate a suspect, victim, or witness to a crime. A seasoned crime scene investigator will possess good instincts as to where the relevant evidence will likely be located. Yet once again, there is the inevitable reality; not all evidence can nor will be located by relying on normal expectations. The best method is a systematic and structured basic approach. Underlying the search process are two general issues: Where should you look for the evidence, and how should you actually conduct the search process?

General Concepts of Crime Scene Searches

Although the preliminary scene survey provides the investigators with some idea as to evidence at the crime scene, to search a crime scene properly for physical evidence it is necessary to view the crime scene in its entirety and not just from the perspective of evidence collection. To accomplish this task, it is useful to examine areas which you normally do not examine. Also, look for evidence from different vantage points, for example, at floor level and at an elevated level. It is extremely important to be cautious and take the time necessary for a methodical, systematic search. This approach ensures that critical evidence will not be damaged or overlooked. Also, look for what is not present or what is missing from the scene.

Although there are numerous exceptions, specific crimes regularly generate different kinds of physical evidence. Excellent and productive crime scene searches are based on logic and an analytical approach to the particular scene. Although there is an inherent danger of jumping to conclusions and losing objectivity, it is most beneficial to logically deduce the types of evidence expected and potential locations of that evidence based upon the general type of crime committed (see Figure K.1).

FIGURE K.1 Disappearing bloody footwear impressions do not mean that the source is flying away (Courtesy of Allison Parrott)

Crime Scene Search Patterns

Crime scene search patterns are varied, are outwardly different in style and application, and provide a structure and organization to ensure that no physical evidence is missed at the crime scene. There is no single correct search method for a specific type of crime scene. Most of the basic search patterns employ a geometric pattern (see Figure K.2). The six basic search patterns are the line, grid, spiral, ray, zone, and link methods. If there is any doubt that some evidence may have been overlooked, then an easy-to-use, basic search method should be employed. Note that some search methods are better suited for outdoor scenes, whereas others work best for indoor crime scenes. Of course, any physical evidence found must be immediately documented using the techniques discussed in earlier exercises.

FIGURE K.2 Six geometric search patterns

1 Link Method

The link method is a productive and common approach for crime scene searches. This method is based on the four-way linkage theory, seeking to find associations between the scene, victim, suspect, and physical evidence. It is a systematic and logical method of gathering physical evidence that can be linked to a particular crime or activity. Although this method is not a geometric pattern or easily definable, it is nonetheless a systematic approach. For example, a victim with a gunshot wound leads to a firearm, a projectile, casings, gunshot residue, etc. The linkages are applications of common logic.

2 Line (STRIP) Method

Outdoor crime scenes can be large in scope and difficult to search because of vegetation, topography, water, and area to cover. One of the easiest patterns to employ that is still very effective is the line method. This geometric pattern involves the establishing of a series of lines or strips in the scene. Members of the search team are arranged at regular intervals, usually arm’s length, and proceed to search ...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Preface and Introduction
• Foreword
• Acknowledgements
• Section I: Crime Scene Investigation: Scientific Methodology and Physical Evidence
• Section II: Initial Responsibilities and Beginning Scientific Crime Scene Investigation
• Section III: Crime Scene Documentation
• Section IV: Physical Evidence at Crime Scenes
• Section V: Crime Scene Reconstruction
• Appendix. Solutions and Reagents
• Index