通过对特定案件现场遗留的剪切痕迹检验确定剪切工具的种类,品牌和型号.根据现场遗留的28个剪切断头反映的刃口特征确定剪切工具为断线钳;对剪切面和立顶上的线条状印压痕进行检验,确定作案断线钳刃顶和刃侧的特殊加工花纹特征;对案发附近区域销售的27个品牌断线钳的刀片加工花纹特征进行取样排查,初步锁定作案工具为“顺利”牌450型断线钳;对生产“顺利”牌断线钳厂家进行调查,实地观察该型号断线钳两个刀片的加工过程,确定其加工特征的相对稳定性.破案后,认定现场断头是一把“顺利”牌450型断线钳剪切形成.因此,对于具有特殊加工花纹特征的断线钳在现场形成的剪切痕迹,在一定范围内进行市场排查,结合特定的加工设备及工艺,可以确定其品牌和型号.

In the case investigation with tool marks, it is very important to analyze the features of the impressed or striated mark with the purpose to determine the class, brand and model of the suspect tool. A successful analysis of toolmarks related to a railway damage case is introduced in this paper, in which the class, brand and model of suspect tool were identified by the manufacturing features. Based on cutting features of 28 broken ends of rebar/steel wire found in the crime scene, the preliminary deduction was made that the cutting tool was a bolt cutter. By examining the inclination in two sides of broken ends and the linear kerfs of the bulge, the special manufacturing features on the top and edge of the blade of suspect tool were identified. 27 brands of bolt cutter were collected from the local market and examined in the laboratory. The “Shunli” brand of bolt cutter was found to have the same manufacturing features as those of the suspect tool. To further confirm the relative stability and individuality of the manufacturing features revealed by the sample bolt cutter, an investigation into the manufacturing process of the type 350,450,600,750,1050 of “shunli” bolt cutters was carried out, and the individual characteristics of type 450 matched the suspect tool perfectly. The suspect was convicted, and a type 450 of bolt cutter was recovered, which was confirmed to be responsible to the mark in the crime scene.