Video: Why Laser Scanning Is Integral to Crime Scene Unit Management
If laser scanning is used to capture a crime scene, and the data is used for scientific analysis and subsequently presented as evidence in a criminal trial, what are the requirements for accuracy and precision? Are all laser scanners up to the task? How can the instrument be validated? Michael Cunningham, a retired CSI specialist from the New York City Police Department (NYPD) and author of the textbook, “Crime Scene Unit Management: A Path Forward,” addresses key questions in this hard-hitting interview.
CHRISTINE: So the first question I have for you is about the use of laser scanning in criminal investigations, why is this topic becoming more and more popular among public safety professionals?
MICHAEL: Well, when we look at crime scene investigation and criminal investigations in general, there’s an expectation by the court that the crime scene will be documented, thoroughly, accurately, in as is condition, the way it was found by the police when they first arrived. That enables other people to view the scene, to make judgments, to reach their own conclusions in a court of law. So when we look at laser scanning, it really brings a whole new dimension to how that’s done. A laser scanner captures the scene in 360 degree images and also in point clouds, and then with the proper laser scan you could reach scientifically accurate conclusions through those measurements that could be gained from those point clouds. So, laser scanning has brought a whole new dimension to crime scene investigations, and it’s really become pretty prevalent in the crime scene investigation community.
CHRISTINE: The more that public safety professionals learn about laser scanning, the more they’re interested in applying it in their own agencies. But they also have some concerns—and so not everyone has adopted the technology yet. What are some of the biggest misconceptions that you think public safety professionals have about laser scanning?
MICHAEL: Yeah, there’s definitely some misconceptions out there. And probably the biggest ones would be the initial cost of the equipment and also the complexity in learning how to use it and deploying it to a scene. So when we talk about the complexity, today’s laser scanners as we know, they’re self-contained units—really portable, easy transportable to a crime scene, hard drives built in to them, with computer operating systems in them, touch screens. The interface between the user and the machine has really become pretty simple. I’ve spent some time training crime scene investigators and using laser scanners, and within a day or maybe two days, they can become pretty proficient at deploying a laser scanner to the scene. The complexity and processing the data later on is a skill that’s built up over time, so learning software applications is something that crime scene investigators will build up expertise in as they use the instrument more and more. The other misconception probably is cost, and it’s true that the initial equipment cost for laser scanning equipment and accessories is significant. But when you look at the value that it brings to crime scene investigation and then you think about the length of time the equipment will be in service, it really becomes extremely magical. We have agencies that have been scanning for seven years now with the laser scanner, and even if they were only processing 2-3 crime scenes a week with that scanner, the overall cost to process a crime scene in laser scanning may be down to say, $100 or so. So is it worth $100 to be able to document the homicide scene in three dimensions? To be able to take a jury back into it later on and let them see the scene in 3D, acquire measurements, answer questions? The answer is pretty obvious: Yeah, it’s very valuable. So when you think of cost, agencies should really think more about the value that it brings the investigation, not the initial cost of the equipment.
CHRISTINE: Sure and you also have the speed of documentation and the completeness of documentation as well.
“Yeah, there’s definitely some misconceptions out there. And probably the biggest ones would be the initial cost of the equipment and also the complexity in learning how to use it and deploying it to a scene.”
MICHAEL: Yeah, you could even offset that cost and maybe even turn it into a positive, because as investigators get more and more proficient when using the laser scanner at the scene, they save time. So the time it may take to hand draw a sketch of the scene and pull a tape measure across the scene to take maybe hundreds of measurements could be done in maybe minutes with the laser scanner. So there’s a cost savings there, which is manpower savings.
CHRISTINE: When you have an agency who decides that they’re ready to make the leap, they see the value, what are some of the key criteria that they need to keep in mind when they’re looking at a laser scanner?
MICHAEL: All laser scanners are not created equally. In crime scene investigation, some equate it sometimes to cameras. There are a lot of cameras on the market, they all take photographs; there are also several laser scanners and they capture laser scans. But they’re not all created equally, so you have to look at what’s important to you, what are your accuracy requirements, what are the data requirements, how will you store the data, what will you do with it. One thing becoming more and more common in crime scene investigation is the need to validate equipment before it’s used at a scene. Not all laser scanners will allow you to do that. There are some, like the Leica ScanStation laser scanners, for example, that will let you validate the scanner before you deploy it at the scene, before it actually captures measurements that you’re going to use to reach conclusions about somebody’s guilt or innocence. You could validate that those measurements are actually going to be accurate. Things like tilt compensation and twin target poles — these certified, traceable measurements become very important, and agencies definitely need to consider that before they get into laser scanning.
CHRISTINE: Sure, that makes a lot of sense. Now, as a result of recommendations made by the National Commission on Forensic Science, there is an initiative underway to require all forensic science service providers in the US to become accredited by the year 2020. How does this initiative affect the integration of laser scanning into criminal investigations?
“One thing becoming more and more common in crime scene investigation is the need to validate equipment before it’s used at a scene. Not all laser scanners will allow you to do that.”
MICHAEL: Yeah it’s definitely going to have an impact, and yesterday, Dean Gialamas, one of the nation’s foremost forensic experts, was right here at HxGN LIVE and presented on that very topic. Back in November of last year, the attorney general agreed to the commission’s recommendation that accreditation be mandatory for all forensic science service providers. And crime scene investigators are forensic science service providers. They operate generally outside of the laboratory but are now being brought into the envelope under forensic service providers. So some of the requirements that they’ll need in order to meet accreditation standards will be to validate equipment, have known accuracy. So when you deploy a laser scanner to the scene, what’s the accuracy of the measurements that you’re expecting it’s going to be able to capture? Is it known, has it been validated? Are there papers on that to prove it? And not just simple accuracy—when an investigator tests one, they have to understand things like positional accuracy, 3D positional accuracy, angular accuracy, distance accuracy—it’s not just a simple statement. So there are things there that are going to be important in accreditation, and having the right equipment that’ll be able to meet those standards will be very important.
CHRISTINE: With the need for accreditation, are there any other questions that public safety professionals should be asking as they take a look at new technology—laser scanning and whatever else might be coming down the road?
MICHAEL: Yeah, as the accreditation standards come down there are different ISO standards that will apply. So they need to look at these standards and understand what they’ll mean. The attorney general’s recommendation mandates accreditation by the year 2020 for forensic science providers. So within that short time frame, any equipment that’s being acquired is going to need to be able to meet those standards. So can you use instruments at the scene to trace your measurements back to national standards, back to traceable standards? Can you validate the instrument at the scene before it’s used? After it’s used, what will you do with the data? How will you store it? How will you maintain it? Once the data is captured, it’s considered evidence. So how will it be verified that it’s valid at the time it’s collected all the way through the time of storage until the time it’s presented in court? Has it been altered? Where has it been? Can you produce the originals? Some software happens to be very good at maintaining the original files, like IMS Map360. The original files are never altered. You could create presentations and you could enhance data, but the originals are always there; it’s always possible to step backwards and go back to the original that was captured at the scene. That’s critical to allowing other professionals to be able to take the original data and reach the same conclusions that the crime scene investigators reached.
CHRISTINE: These are all very critical considerations. Now, you have a new book that was recently published that addresses a lot of these different issues along with some other topics. Do you want to talk about that book for a moment?
MICHAEL: Yeah, sure. I actually brought a copy along here. It’s “Crime Scene Unit Management: A Path Forward.” When we talk about the changes that are coming in forensics, they all stem back to a National Academy of Science report that was released in 2009, titled Improving Forensic Science in the United States: A Path Forward. I collaborated on this book with two other authors, Ed Wallace and Dan Boggiano, both lifetime experienced crime scene investigators. And when we looked around we realized there’s a lot of text out there about how to process crime scenes—how to collect fingerprints, how to collect DNA evidence, how to handle it, how to test it. But there weren’t many texts out there on how to manage the entity, the crime scene unit entity. And especially on the path forward, where accreditation will become mandated, how do you take your unit from the point it’s at through an accreditation process to meet new national standards that are forthcoming? And how do you accomplish actually improving forensic science? So that’s what the book is about. We’re excited, and we’re hoping that it will be helpful to the practitioners in the field.
CHRISTINE: It certainly sounds that way. Now where can people get a copy, is it available through Amazon.com?
Michael J. Cunningham is a retired New York Police Department 1st Grade Detective. He served for 26 years as a latent fingerprint officer, evidence technician and crime scene investigator, and assisted in developing standard operating and quality assurance procedures for the crime scene unit. He teaches at the National Center for Biomedical Research, which is a provider of emergency responder training for the U.S. Department of Homeland Security, Office of Domestic Preparedness. He also teaches crime scene investigation techniques internationally on behalf of the U.S. State Department’s Anti-terrorism Assistance Program. Cunningham is a recognized expert in shooting reconstruction and 3D laser scanning. He currently works with Leeds LLC to provide Crime Center case management solutions to the law enforcement community.
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