Homicide Scene Documentation with 3D Laser Scanning

Kansas crime lab’s trial test of new Leica Geosystems 3D laser scanner at a homicide scene provides a powerful demonstration of the forensic tool’s superiority over traditional methods of crime scene mapping.

On Easter Sunday 2010, police detectives responding to a homicide within the Kansas City metropolitan area requested the Johnson County Criminalistics Lab to dispatch its crime scene investigation unit. For Ryan Rezzelle, supervisor of the lab’s five crime scene investigators, the call represented an unexpected opportunity. Just two days earlier, Rezzelle had received on loan from Leica Geosystems the newest model ScanStation C10 3D Laser Scanner which he and his team had been testing as a forensic instrument for crime scene mapping.

“I thought, ‘What better way to compare the ScanStation’s capabilities with our current mapping methodologies than to use it at an actual crime scene,” Rezelle said. “We could piggyback the scan data collection without any intrusion. That would provide a real-time field trial test and a side-byside comparison with the protocols used and evidentiary data obtained by the police traffic accident investigation teams that are currently called upon to do the measurements.”

约翰逊县犯罪实验室正在考虑尖端法医测量技术并不奇怪。The lab, administered by the Sheriff’s Office, serves a population of over 560,000 residents in both the rural and urban areas on the Kansas side of the greater Kansas City metropolitan area, and has a reputation as one of the most progressive, well-equipped high tech crime labs in the country. Both Sheriff Frank Denning, long a believer in the value of highly professional forensic services, and the lab’s director, Gary Howell, were strong proponents behind the recent commencement of construction planning on a state-ofthe-art crime lab, slated to open in early 2012 in Olathe, Kansas.

In addition, the lab is accredited by the American Society of Crime Laboratory Directors Laboratory Accreditation Board under the ASCLD/LAB International Program, a comprehensive accreditation that has been earned by only about five percent of the crime labs in the U.S.

After obtaining permission from the lab’s quality assurance manager to trial the ScanStation, Rezzelle and his team investigated the crime scene, the focus of which was the body of a man shot to death in the front seat of a car. Mounting the scanner on its tripod, the investigators conducted three exterior scans within 45 minutes, along with the associated digital photographs. “The set-up and scanning was fast and easy,” Rezzelle said. “We had learned the procedure in about half an hour on Friday with the Leica representative remotely talking us through the process on a speaker phone.”

在受害者的尸体已被从the car, the team removed the scanner from its tripod and placed the unit on a special Leica accessory mount on the car’s center console armrest and captured a 360 degree scan of the car’s bloody interior. A second 360 scan was conducted from the rear seat for a total of five scans.

“What amazed us was, from set up to the time we put the scanner away, we were there maybe sixty to ninety minutes, tops,” Rezzelle recalled. “Compare that to the traffic accident unit, a two man crew using a total station and prism poles, along with their tape measures, hand-held laser distance measuring tools, and Rolatapes, who worked for eight to ten hours marking and measuring single points. We had captured the same scene with literally millions of points in a fraction of that time.”

Late the following day Rezzelle overnighted the laser scanner to Leica Geosystems’s Georgia headquarters, following which a technician there quickly processed the five scans and “stitched” them into a single “point cloud.” Two high-value exhibits were then generated from the data consisting of a 3D fly-through of the crime scene and a Leica TruView. (Leica TruView is a free plug-in for Internet Explorer which allows CSIs to quickly and easily share scene data with command staff, detectives and prosecutors. TruView was recently used in a Georgia homicide trial to virtually place the jury at a crime scene.)

For agencies that have purchased a Leica 3D laser scanner, this procedure is performed by in-house personnel who have completed a police oriented training regimen developed by Leica Geosystems. In all, the process took five to six hours, the great majority of which was computer “rendering” and processing time. By Friday morning the results were in Rezzelle’s hands.

“我们被吹走了。每个看到它的人也是如此。”雷泽尔说。“我们从汽车内部捕获了一些出色的数据，通过将所有五张扫描拼接在一起，我们有许多可用的证据。弗兰克·丹宁（Frank Denning）警长对苍蝇的动画印象特别深刻。就个人而言，这是我多年来见过的犯罪现场最令人印象深刻的演讲之一。因此，即使我们认为我们的急速考验，我们也产生了一种可以由检察官，CSIS，律师和犯罪现场重建主义者来看的东西，作为出色的输出，以获得良好的清洁清晰的视角，以了解不同组件在不同组件的关系上犯罪现场。”

Three dimensional laser scanning has recently taken on additional importance in criminology in the wake of the 2009 report by the National Research Council (NRC), a committee of the National Academy of Sciences (NAS). Titled “Identifying the Needs of the Forensic Science Community,” the report focuses on strengthening the current benchmark standard published by the International Organization for Standardization (ISO), commonly called the ISO 17025. Historically, crime scene response units in most U.S. police agencies have been routinely exempted by their management from the requirement to become accredited. That attitude is changing fast as a growing number of agencies seek accreditation for their crime scene units in a tacit acknowledgment that ISO 17025 protocols should begin at the crime scene and not wait until the evidence reaches the crime laboratory.

Rezzelle坚信Leica Geosystems扫描仪C10激光扫描仪将扮演重要角色：“我认为这就是NAS想要的。一旦人们看到了C10可用的输出，就会期望这将用于捕获美国的每个犯罪现场。他们[NAS]呼吁法医学基于科学，这就是我们在这里所拥有的。这是说明的。从视觉上看到的内容是描述性的。这将是犯罪现场的下一代映射。”

Written by Tony Grissim