Success Rate of Forensic Surface Search for Osseous Remains in a New England, USA, Environment

Abstract

Human skeletal remains in outdoor forensic sites often are dispersed from their point of initial deposition, making locating isolated bones difficult. Forested areas in particular may obscure remains, as bones stained from soft-tissue and leaf-litter decomposition may blend in with the forest floor or be hidden by understory. Wide skeletal dispersal presents other problems for searchers, including the difficulty in keeping track of which areas have been searched and maintaining proper spacing of searchers to prevent gapping. Little is known about success rates when searching for dispersed skeletal elements and the effects of searcher spacing, searching the same area twice, type of skeletal element, and understory growth. In order to test recovery rates searching through forested areas, isolated postcranial elements of white-tailed deer (Odocoileus virginianus) and crania of pigs (Sus scrofa) were laid out randomly in a large grid system and searched for. Overall recovery rates for n = 500 elements were 84.0% on the first pass-through and a cumulative total of 90.0% after the second pass-through, with 10.0% missed after both. Significant differences in recovery rates based upon bone type were noted, but no significant difference was found based upon searcher spacing (1 m vs. 2 m) or understory density (low vs. medium). Forensic archaeologists should note that even with careful searching under controlled conditions, exposed surface skeletal elements can be missed, a concern that is likely amplified under real field search conditions. To maximize remains detection, forensic search protocols should include narrow searcher spacing and double passes through search areas wherever possible.