Abstract：
In cases of criminal dismemberment, the analysis of saw marks helps to determine the class of the saw used. The present study compared the microscopic features of experimental false starts performed on three freshly defleshed human femurs. 150 lesions were produced using three reciprocating blades and two hand saws of similar class. Two groups of tools were created according to the class of the blades: group 1 (teeth per inch = 6, alternating set) and group 2 (teeth per inch = 24, wavy set). The minimum width of the kerf was always thicker with reciprocating blades than that of the handsaw of the same class. This fact is linked to the thickness of the blades and not necessarily to the fast forth and back motion of the blades. Shape kerf profiles and shape of the walls were very confusing, with a lot of variation of the false starts caused by the reciprocating blades and the risk of misclassification (rip teeth versus crosscut teeth, alternating set versus wavy set). Striae on the kerf floor and bone islands were more consistent. The main conclusions are, first, that usual features of false starts achieved by reciprocating saw blades used in this work vary a great deal and may lead to misclassification of the saw class, and second, that no criterion has been found to differentiate reciprocating blades and handsaws. These results demonstrate that we have to be very prudent while estimating the possible saw from a false start in a real forensic case.
摘要：
在刑事肢解的情况下，锯痕的分析有助于确定使用的锯的类别。本研究比较了在三个刚偏转的人类股骨上进行的实验性假启动的微观特征。使用三个往复式刀片和两个类似类别的手锯产生了150个病变。根据刀片的类别创建两组工具:组1(每英寸齿=6,交替组)和组2(每英寸齿=24,波状组)。往复式刀片的切口的最小宽度总是比同类手锯的最小宽度厚。这一事实与叶片的厚度有关,而不一定与叶片的快速前后运动有关。形状切口的轮廓和墙壁的形状非常混乱，由于往复式叶片引起的错误启动的变化和错误分类的风险（撕裂齿与横切齿，交替集合与波浪形集合)。切口底板和骨岛上的条纹更加一致。主要结论是,首先,在这项工作中使用的往复锯条实现的错误启动的通常特征差异很大，可能导致锯类的错误分类，第二,没有发现区分往复式刀片和手锯的标准。这些结果表明，在真实的法医案件中，我们必须非常谨慎，同时从错误的开始估计可能的视线。
