A Casting Method for Physical Match of Objects with Curved Surface
Yuan Guo-pin · Xingshi jishu · 2015
Evidential fragments are often encountered at crime scenes, particularly those involving in motor-vehicle accidents and crime. The objects are often broken from external force, leading to fragmentation. However, due to the complex structure of the object's surface and the large number of fragments, fitting all the fragments together becomes extremely difficult. Here the fitting methods, implementation steps and operation specifications for reassembly under different circumstances were tested and optimized. Overall separation tests of 30 surface-different objects under 50 various conditions were implemented to identify the fragments and the amount of the original objects. The high-strength materials and their auxiliary for three-dimensional footprint lining extraction were utilized to cast corresponding object's liner(lining) models by perfusion or adhesion methods. The model, as a framework, was compared with the relevant debris to put them together. The reconstruction of a glass bottle was taken as a specific example to illustrate the test procedure. The new method has proven its practical value for the examination and identification of similar broken trace evidence. The standardized examining steps and related precautions were also proposed.