Forensic Anthropology Program, Department of Anatomy and Neurobiology, Boston University School of Medicine, Boston, Massachusetts, USA.
Massachusetts Office of Chief Medical Examiner, Boston, Massachusetts, USA.
J Forensic Sci. 2021 Jan;66(1):25-43. doi: 10.1111/1556-4029.14556. Epub 2020 Sep 21.
Most studies of saw marks have focused on morphological characteristics and their utility in identifying saws suspected to have been utilized in cases of criminal dismemberment. The present study examined the extent to which metric analysis may be used to correlate saw blade measurements with minimum kerf widths (MKWs). A sample of 56 partially defleshed white-tailed deer (Odocoileus virginianus) long bones was utilized as proxy for human remains. The long bones were cut using a variety of commercially available saws, including 11 manual-powered and 5 mechanical-powered saws. A total of 496 false start kerfs (FSKs) were created. Two experiments were performed, with the first test examining the MKWs of FSKs produced on specimens that were restrained using a bench vise, while the second test analyzed the MKWs of FSKs produced on minimally restrained specimens. Statistical analysis using Hierarchical Linear Modeling (HLM) indicated a positive relationship between saw blade width (mm) and MKW, with blade width (p < 0.001) and the overall difference between the mechanical- and manual-powered saws (p = 0.029) tested, reaching statistical significance. A comparison of MKWs produced using manual-powered saws on restrained and minimally restrained bones suggests that restraint condition (p = 0.009) has a statistically significant effect. In comparisons of MKWs to blade widths, the average ratio for mechanical-powered saws is 18.7% greater than the average ratio for manual-powered saws. While the mode of the ratios was 1.42, thus supporting the general rule that MKW does not exceed 1.5 times blade width, multiple individual ratios did surpass 1.5.
大多数关于锯痕的研究都集中在形态特征及其在识别涉嫌用于刑事肢解案件的锯子方面的效用上。本研究考察了度量分析在多大程度上可以用于将锯片尺寸与最小锯缝宽度（MKW）相关联。利用 56 根部分去肉的白尾鹿（Odocoileus virginianus）长骨作为人类遗骸的替代品。这些长骨是用各种市售锯子切割的，包括 11 个手动动力锯和 5 个机械动力锯。总共产生了 496 个假启动锯缝（FSK）。进行了两项实验，第一项测试检查了在使用台虎钳固定的标本上产生的 FSK 的 MKW，第二项测试分析了在最小约束标本上产生的 FSK 的 MKW。使用层次线性建模（HLM）的统计分析表明，锯片宽度（mm）与 MKW 之间存在正相关关系，其中包括刀片宽度（p<0.001）和机械动力锯与手动动力锯之间的总体差异（p=0.029），达到了统计学意义。比较在固定和最小约束条件下使用手动动力锯产生的 MKW 表明，约束条件（p=0.009）具有统计学意义。在比较 MKW 与刀片宽度时，机械动力锯的平均比值比手动动力锯的平均比值大 18.7%。虽然比值的模式为 1.42，因此支持 MKW 不超过刀片宽度的 1.5 倍的一般规则，但多个比值确实超过了 1.5。
