Crime Scene Documentation

Preserving the Evidence and the Growing Role of 3D Laser Scanning

Robert Galvin

• Publisher: CRC Press
• Year: 2020
• Print ISBN: 9780367652302
• eBook ISBN: 9781000334746
• Topic: Law
• Subtopic: Forensic Science
• Index: Law

When a criminal act or vehicle crash occurs, most often a local law enforcement agency responds and is responsible for both investigating the scene and for documenting it. It is critical that scene evidence is collected and recorded efficiently, as the scene can quickly change. The sooner evidence can be collected, reviewed, and analyzed, the better an understanding investigators will have as to how and why the incident occurred.

Crime Scene Documentation: Preserving the evidence and the growing role of 3D laser scanning demonstrates at length the value of laser scanning through the use of numerous case studies of investigators who have utilized various 3D technologies and laser scanning to document scenes. Thorough and accurate scene documentation is an essential function at a science and proves particularly valuable in courtroom presentations to help jurors understand a crime or accident's likely chain of events. The more advanced a scene documentation method is, the better it can be utilized to capture details that will lead to optimal scene diagramming.

Currently, 3D laser scanning is the most advanced method of scene documentation available, capturing detailed and realistic digital scans—capturing scenes in their entirety—and yielding a permanent representation of the scene for study and analysis at any time, even years after a crime scene has vanished. The book explains current technology, the latest advances, and how to best utilize the technology. Case examples come from various applications, from tools to programs, can help crash scene investigators understand how scanning can improve scene documentation, provide better and more evidence details, and build more credible diagrams that possibly may be used in court presentations to help support a case.

Key Features:

• Describes 3Dscene recording methods in use and how well they work
• Outlines the variables and inherent challenges associated with documenting crime and crash scenes
• Illustrates the positive, and dramatic, impact of having a well-documented scene, particularly in the courtroom

• Explores how 3D laser scanning has vastly changed the way and extent to which crime and crash scenes can be captured accurately and completely, and subsequently analyzed
• Explains how laser scanning is highly flexible and presents strategies to integrate it into other crime scene incident recording techniques and technologies

Crime Scene Documentation details the many benefits of 3D laser scanning technology relative to its reliability and accuracy as well as the multiple case scenarios in which it can be used. The book serves as an invaluable resource to crime scene technicians, investigators, and reconstructionists on the best ways to document a crime or crash scene.

PART I

Introduction

The Importance of Crime Scene Documentation and the Drive to 3D Scene Visualization

On February 21, 2014, a student of San Jose State University called the emergency helpline, 911 to report a man with a large knife stabbing the air and acting erratically. Two university police officers confronted the man, who was carrying a footlong, drywall saw and appeared to be mentally unstable or intoxicated. When a Sergeant and Officer arrived at the scene, they ordered the man to drop the saw. When he refused and kept advancing, they used a stun gun to try to subdue him. These actions, however, did not deter the man, and he charged at one of the officers, so the second officer shot him twice in the back, killing him. The officer that the assailant charged at wore a shoulder-mounted body camera that recorded the events from his point of view.

Media coverage of the event focused on how the man with the saw was shot in the back. A civil lawsuit claiming wrongful death ensued, saying the body-camera video clearly showed the man was trying to run away from the officer when he was shot.

A forensic company combined its laser scanner and a drone to thoroughly document the three-block crime scene in a minimum amount of time. The data captured was used to digitally preserve both the smallest details of the scene and a macro, over-head view that included the roofs of vehicles and buildings. This data was used to clarify the body-camera footage that was taken at the scene and determine measurements critical to the case. Ultimately, with the aid of this technology, the shooting was determined to be justifiable¹ (Figures I.1 and I.2).

Figure I.1 Shown is body-worn camera footage of an officer chasing a saw-wielding assailant down a street near San Jose State University. When the assailant approaches the officer, the officer shoots him. A forensic scene visualization company reconstructed scene events by using a 3D laser scanner and drone to record a dimensionally accurate, 3D model of the scene to clarify events filmed with the officer’s body-worn camera. (Photo courtesy of www.visuallaw.com.)

Figure I.2 The scanned data captured from the officer-assailant chase scene was used to create a “virtual camera” that could be matched to the scanned scene’s point cloud. Shadows from the virtual camera were accurately placed into the point cloud so distance between the officer and suspect could be measured. (Photo courtesy of www.visuallaw.com.)

This case underscores an inarguable point, which is that whenever and wherever a crime occurs, two actions are required without exception: the crime scene must be investigated, and it must also be thoroughly and accurately documented. These essential actions are more technically known as forensic mapping because they comprise two separate sciences that go hand-in-hand as crime scenes, and their evidence are probed. More importantly, a forensic investigator has the training and knowledge to understand and identify crime or crash scene evidence, how it can best be documented, and present his or her findings in court.

The scene documentation component of forensic mapping is the emphasis of this book because today's crime scenes are being documented more comprehensively and

accurately than ever before, thanks to new, constantly advancing technologies. From the moment a crime occurs, its scene can reveal a treasure trove of information and details as an investigation gets underway. How the scene is documented can be pivotal for a jury to understand the circumstances of a crime.

This book will explore how the latest scene mapping technology supports the investigator or reconstruction technician as he strives to rebuild the scene with the highest of accuracy, but also in a way that jurors can experience actually being taken inside the scene itself via a 3D perspective.

The Drive to 3D Scene Depiction

Crime scene mapping technology progressed slowly at first. For years, tape measures and measuring wheels were the accepted ways to map a scene, and the scenes themselves were portrayed with paper diagrams or sketches. But the diagrams, coupled with scene photographs, had to be explained extensively to juries who may not have fully understood scene events. Eventually, the total station, predominantly used in field surveying, was discovered to have a perfect fit for mapping crash scenes and crime scenes. The total station then secured “king-of-the-hill” status in mapping these types of scenes for decades. It is still widely used today. But when the 3D laser scanner arrived, it represented the tipping point for crime scene investigation because the scanner could map and record the scene in three-dimension and in totality, within a fraction of the time required by older methods. From this juncture, there has been, and continues to be, a non-stop proliferation of all kinds of tools that can achieve 3D scene visualization—3D cameras, tablets and drones, for starters. The availability of such a wide spectrum of technology addresses several pressure points in

our crime scene documentation environment. Here are a few of them:

• Crime scenes, in many instances, have become larger and more intricate to map and capture, oftentimes with immense amounts of evidence to sift through and document.
• Analysis of evidence, and perspectives of how a crime scene's events may have unfolded, require heightened priority and visualization—especially in 3D—now that juries have become savvier and demanding about how scenes should be depicted in court.
• Vastly improved technology for documenting crime scenes is fueling the need for complete evidence, numerous scene angles and perspectives, and analysis, all of which can be included in and/or supplement software-generated diagrams.
• As crime scenes proliferate, there has been increased pressure within law enforcement to close cases faster, which is prompting the adoption of more efficient technologies that can speed up scene mapping and recording.
• Cost and affordability of crime scene reconstruction technology continues to be a factor in what technology tool an agency or private reconstruction expert can afford and purchase.

Laser Scanning Becomes a Major Technology, But No Longer Used Exclusively

This book will explore how the various technologies are used today for mapping and documenting crime scenes. It will also explore the relevance, use, and merging of tools in crime and crash scene investigations by investigators and reconstruction experts. There has been a significant shift toward 3D crime scene capture and diagramming, primarily driven by the demand among juries to better understand how events during crash and crime incidents most likely occurred. In the book, as many relevant technologies as possible will be probed and validated by commentary from professional crash and crime scene reconstruction experts who actively use them.

As you read this book, you will see that it emphasizes one crime scene documentation technology in particular: 3D laser scanning. Laser scanning has emerged over the years as a necessary scene recording tool that is used by investigators and reconstruction technicians. However, it is not the only tool in the toolbox for crime and crash investigations. This book will cover a variety of technologies as well as devote the last chapter to how valuable it can be used to combine two or more of these tools to reconstruct a crime or crash scene. Each of these tools—whether it is a tablet, total station, or drone—can play a role in helping to rebuild a scene, while also able to complement laser scanning.

In this book, we will discuss the modern technologies available for crime and crash scene investigations, but by no means does this mean the discussion can be comprehensive with the speed of innovation in our lives. Products are becoming lighter, faster, smaller with each iteration, and mobile phones are mini portable walking computers. New technologies help create new possibilities, but the benefit can only be realized when quality can be guaranteed all-time.

It is only reasonable for forensic science experts to pause in their professional lives to observe just how technology pervades their work and what trends shape how they recreate the crime scenes of today and especially of tomorrow. It seems safe to say that technology is not just here to stay, but that it will continue advancing, helping reconstruction experts uncover how scenes came to be as they strive to solve cases brought before a jury.

Note

1. FARO. “Focus Laser Scanner Used to Clarify Body Camera Film.” FARO Technologies, Inc., 2017. https://public-safety.faro.com/assets/CaseStudy_LaserScanner_Visual_Law_PS_AM_EN.pdf.

1

A Brief History of Forensic Science

How Archimedes and Jack the Ripper Shaped Modern Forensics

Archimedes: The First Forensic Scientist

It seems hard to believe, but forensic science has roots reaching all the way back to ancient times, and without even the slightest hint of what we consider the technology innovations of today. But there certainly was innovation. One standout example is the period of 287–212 BC, which featured Archimedes of Syracuse, a brilliant Greek mathematician and physicist who had other impressive credentials. History considers Archimedes as the father of forensic science. The most famous example underscoring this accolade points to when Archimedes was asked by then-King Hiero to investigate whether or not his royal crown, commissioned to a local goldsmith, was actually made of pure gold, as the king had mandated.¹ The king was suspicious, which is why he asked Archimedes to, we could say, do a bit of forensic sleuthing. Archimedes figured out that the best solution would be a test of the crown for density and buoyancy, whereby the crown’s volume could be determined by the amount of water it displaced. The goldsmith who had created the crown, it turns out, was sneaky, because he only used some of the gold given to him by the king; perhaps he was hoping to save the rest of the gold for his personal use.

The test that Archimedes performed was to calculate the crown's density and, thus, its purity for solid gold. The king's hunch was correct, as the test results showed that only part of his gold given to the goldsmith had been used in making the crown. The experiment marked a true red-letter day for Archimedes, who, thrilled with his discovery, ran down the streets of Syracuse shouting, “Eureka,” which, in Greek, meant “I found it.”² Quite the “Eureka” moment! (Figure 1.1).

Figure 1.1 The tale of Archimedes’ “Eureka!” moment is legendary, and one of the first examples of forensic investigation. The famous Greek mathematician/physicist/astronomer was asked by King Hiero of Syracuse to assess the purity of an irregular votive crown he had given to a goldsmith. The king suspected the finished crown was not pure gold and asked Archimedes to test his suspicion. Archimedes did so while taking a bath, discovering that the crown indeed was not pure gold by its density and buoyancy. (Illustration from Wikimedia Commons)

From this historical period in forensic science's infancy came more innovation, when, in the 70...

Table of contents

• Cover
• Half-Title
• Title
• Copyright
• Contents
• Professional Biography
• Part I Introduction: The Importance of Crime Scene Documentation and the Drive to 3D Scene Visualization
• Part II Getting the Most Out of 3D Laser ScanningA Look at Some Unique Applications
• Index