The criminal justice system relies on eyewitness testimony to discover truth about a crime, and it’s often key in the conviction or exoneration of suspected criminals. However, studies have shown that even honest, well-intentioned witnesses make errors due to psychological factors such as stress and memory. Investigators also encounter false witnesses who intentionally mislead and confuse. So how does one separate fact from fiction?
A first step is establishing whether witnesses actually had a line of sight to the scene of the crime. “That’s an important piece of information,” said Steven Holloway, deputy director of the Wyoming State Crime Laboratory. “It goes back to that whole issue that’s so important in our justice system of, What is the truth?”
A Matter of Focus
Experienced crime scene investigators are highly observant and very good at picking up on small clues. Yet even the best investigators cannot measure everything or predict what might become significant. Take, for example, a scenario in which a horrendous crime is committed outdoors and the scene is processed manually. Right before trial, a witness suddenly comes forward with startling information and claims to have “seen the whole thing” from a motel room down the street. “Well, you wouldn’t have captured that data in your diagrams and measurements of what windows were where in a building down the street that’s not involved,” Holloway said. “Those are things that you don’t think of at the time you’re handling the crime scene because you’ve got this horrific crime right in front of you.”
Conversely, a laser scanner not only focuses on the immediate crime scene but also captures anything and everything in its line of sight and within its range. “It is capturing measurements at your crime scene that you wouldn’t ordinarily capture using any other technology,” Holloway said. This includes surrounding areas that, while not part of the actual crime scene, may become critical to the investigation. For example, if the motel room in the previous scenario was within scanner range, investigators could simply go back to the scan data and, using 3D visualization software, instantly determine whether witnesses could have seen what they said they saw. “That’s incredibly valuable for those types of situations because it is absolutely impossible for anyone to gather or diagram all of the information of the entire area around the crime scene,” Holloway said. “It’s just impossible to do.”
Theory Becomes Practice
For Detective Victor Pizzola, of the Albany Police Department’s Forensic Investigations Unit, which implemented laser scanning in January 2013, this type of scenario is not simply hypothetical. The unit’s Forensic Scan Team has had real-life opportunities to use scan data and 3D visualization software to dispel or support witness testimony in Albany, New York. “The scanner technology today—what it captures, what it can do, the product it puts out in the short period of time—is amazing,” Pizzola said.
Laser scanning technology allows investigators to document the scene and surrounding environs comprehensively and impartially without fear of missing something of key importance. “For me, the biggest thing of this system is that we can go out and scan a scene without knowing every intricate detail in the preliminary investigation stage,” Pizzola said. For example, in a homicide scene, this might mean not knowing which way the perpetrator came from and which way he or she went. “We can go out and do the larger perimeter scan—not just get the evidence, but back up and get the surrounding area.” The exact scene and its environs are virtually frozen in time and available to visit at any point in the future.
If witnesses or involved parties come forward at a later date, they can be brought in for questioning to determine whether their evidence is reliable. A witness may say, “I was standing on the porch of this address.” Using the scan data and 3D visualization software, Pizzola can establish whether the eyewitness actually had a line of sight. “I can take the software and put them right on that porch and point them in the direction they were looking and either dispel or support what they tell us. We’ve done this twice already,” Pizzola said. “In that regard, this thing is amazing.”
Since eyewitness testimony plays a key role in the outcome of a case, it is critical to establish whether witnesses, who are subject to fallibility and deceit, are providing reliable and accurate information. While this may not always be possible, in some cases, laser scan data and 3D visualization software can decisively corroborate or contradict witness claims whenever they come forward. “When you are processing any crime scene, you cannot predict what might become important later on,” Holloway said. “That’s why this technology is so valuable—it captures everything in the vicinity so that you have that information in the future when something new becomes important that you hadn’t anticipated.”
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About the author: Wendy Lyons is journalist living in Canton, Georgia, who spent several years writing about surveying technology for POB magazine. She now focuses on covering laser scanning and other geospatial measurement solutions for public safety professionals.