Frozen Justice: Detecting and Recovering Firearms Evidence at Snow Scenes

Abstract

This research project identifies and explores the complexities associated with the detection and recovery of firearms evidence, namely casings, from areas in which snow is prevalent. By reviewing established crime scene processing methodologies, this research sought to determine what, if any, effect snow has on an investigator’s ability to find and collect casings when they are concealed underneath a layer of solid precipitation. Casings of eight different sizes were used to establish a mock scene at Fort Drum, New York, where the average annual snowfall regularly exceeds 100 inches. Two different brands of metal detectors were used to recover the casings, a Garrett CSI Pro and a Bounty Hunter Tracker IV. Bench tests performed with both detectors in controlled indoor conditions showed consistent responses to a distance of approximately eight inches across the eight calibers and gauges examined. During the recovery experiment approximately one month after initial deposition, the less expensive detector performed poorly when pitted against the more expensive model. The experiment resulted in the recovery of 48 of 80 casings, a 60% recovery rate. Neither detector was able to locate .22 Long Rifle casings at a depth of approximately 7”, indicating a relationship between size of the casing, depth of snow, and strength of the detectors.