Determining the Accuracy of Area of Origin for Impact Patterns Found on Horizontal Surfaces
Jessica Reynolds & Eugene Liscio
Abstract: This research analyzed the accuracy of area of convergence and origin determinations for impact bloodstain patterns found on a horizontal surface. This study was completed by using the bloodstain tool in the FARO Zone 3D software in order to understand the errors associated with an area of origin analysis. Two data sets of impact patterns were created using a wooden piston travelling at 1.19 m/s downward and 2.36 m/s downward. For each data set, five impacts were created at heights of 10, 20, and 40 cm. For each impact, a minimum of 50 elliptical stains were analyzed in FARO Zone 3D. The latitude, longitude, and elevation positions of each area of origin were recorded. The total 2D and 3D errors were calculated for all trials. Relationships between impact velocity and total error, as well as impact height and total error found the elevation position to be the main factor influencing the accuracy of area of origin.
Determining the Accuracy of the ‘Place in 3D’ Function in FARO Scene
Chris Flight & Kaye N. Ballantyne
Abstract: With increased improvements in digital imaging technology and their rapid uptake and use in everyday life, the general public are often recording day to day events as they happen. Law enforcement agencies have also increased the use of body-worn cameras to capture events. Combining 3D laser scan data of a scene with the image or video frame taken at the time of a crime or incident may provide information on the position and orientation of a camera at the time of recording, adding value to a police investigation by providing additional situational and spatial context. This project examined the accuracy of the Place In 3D function in FARO Scene to position an image or video frame from a non-fixed camera in 3D space at the time it was captured. Placement of the camera was accurate to approximately 22 mm, with similar levels of accuracy observed across all camera distances, locations, and camera types tested.
Supplemental Data: 2022-Supplementary Table One-Flight.docx
A Simple Technique for Recreating Certain Eyewitness Perspectives
John C. Paolucci, Matthew Steiner, & Sophia DiCioccio
Abstract: Eyewitness identifications and eyewitness accounts of events are often introduced into criminal investigations and subsequently presented at trials. This study demonstrates a technique for recreating the spatial relationship between subjects, objects, and obstructions in the scene so that the person who is attempting to “stand in the shoes” of the eyewitness is provided with an accurate representation of what the eyewitness saw. When the CSI places a scale in the foreground of the image, the image can be calibrated to that scale and printed out in a one-to-one (1:1) format that will enable the viewer to see the incident location in a similar scale to that of the eyewitness’s perspective. This paper is intended to provide a guide for a CSI to capture information that can be used in a crime scene reconstruction to accurately represent how the scene appeared to an eyewitness. The methodology is designed to enable the CSI and reconstructionist to perform this task without access to specialized equipment. Some caveats exist and are delineated in this report for full clarity.
An Evaluation of Crime Scene Legal Cases Related to Judicial Gatekeeping
Lee Wade & William Shulman
Abstract: After the Supreme Court decision in Kumho Tire Co., LTD et al. v. Carmichael et al. (1999), judges have allowed crime scene investigators to testify as experts related to their knowledge, training, and experience. However, defense counsel normally challenge their type of testimony based upon case law precedent related to rules under various Supreme Court cases and The Federal Rules of Evidence. This paper evaluated legal cases challenging testimonies of crime scene investigators related to the reconstruction of a crime scenes and elements of criminal incidents. The pattern that emerged showed that judges, as gatekeepers of evidence related to expert opinions, generally admit testimony from crime scene investigators and reconstructionists, but often limit the weight of evidence for the jury. It should be noted that although crime scene investigators and reconstructionists were evaluated in these judicial cases, there are differences in reconstruction and initial crime scene investigations. The training and experience of the crime scene expert, and the general information related to the reconstruction of the crime scene, were two of the several variables that influenced the opinion of the judges.