Underhill M
Metropolitan Police Forensic Science Laboratory, London, United Kingdom.
Sci Justice. 1997 Apr-Jun;37(2):121-7. doi: 10.1016/S1355-0306(97)72157-9.
A set of experiments tested the idea that an examiner can distinguish glass acquired by backward fragmentation from that acquired by contact with already-broken glass. A window was broken. The exterior surface of the breaker's clothing was brushed and hair-combings taken and these were searched for glass fragments. Wearing the same clothing the breaker then cleared up the broken glass and further hair-combings and brushings of the clothing surface were taken. The size, shape and presence or absence of an original flat surface was recorded for the recovered fragments. The distributions within these parameters were compared for the two methods of acquisition and association between the method and the parameters was tested using contingency tables. It was found that fragment shape does not identify the method of acquisition and that a high proportion of fragments retaining the original outer surface shows that the glass was acquired by backward fragmentation.
一组实验验证了这样一种观点，即检查人员能够区分通过反向破碎获得的玻璃和通过与已破碎玻璃接触获得的玻璃。打破一扇窗户，刷取破坏者衣服的外表面并采集头发样本，然后对这些样本进行玻璃碎片搜索。破坏者随后穿着相同的衣服清理破碎的玻璃，并再次刷取衣服表面和采集头发样本。记录回收碎片的尺寸、形状以及是否存在原始平面。比较这两种获取方法在这些参数方面的分布情况，并使用列联表检验获取方法与参数之间的关联。结果发现，碎片形状无法识别获取方法，并且很大一部分保留原始外表面的碎片表明玻璃是通过反向破碎获得的。
