Cooper Guy
Keith Borer Consultants, Durham, UK.
Sci Justice. 2013 Jun;53(2):166-70. doi: 10.1016/j.scijus.2012.06.003. Epub 2012 Jun 30.
Experiments were conducted to investigate a scenario sometimes encountered in casework, where a police officer has attended a scene and shortly afterwards arrested a suspect. The experiments involve the transfer of glass fragments from a surface scattered with broken glass to a hand, and then from the hand to the sleeve of a poorly retaining jacket. The persistence of the transferred fragments was studied by collecting the glass fragments as they fell off the jacket, whilst the wearer was walking on the spot. The recovery regime allowed the number and proportion of fragments picked up and transferred to the jacket from the hand to be determined, and the rate at which they were lost from the jacket to be monitored. The results show that large numbers of glass fragments can be picked up on a hand from a suitable surface. A subsequent firm grip to a poorly retaining jacket was found to transfer a significant proportion of the glass fragments from the hand to the jacket. In seven of nine tests performed, ten or more glass fragments were recovered from the jacket 60 minutes after the original contact between the hand and the broken glass. More than twenty fragments were recovered in three of these tests. Consequently, where possible and appropriate, the full circumstances of a case should be considered carefully before indirect transfer is ruled out as a possible explanation for recovered "matching" glass. This is the case even for poorly retaining clothing.
进行了一些实验，以研究在案件调查中有时会遇到的一种情况，即警察到达现场后不久逮捕了一名嫌疑人。这些实验包括将玻璃碎片从散布着碎玻璃的表面转移到手上，然后再从手转移到一件不易留住碎片的夹克袖子上。通过在穿着者原地行走时收集从夹克上掉落的玻璃碎片，研究转移碎片的持久性。回收方案能够确定从手上捡起并转移到夹克上的碎片数量和比例，并监测它们从夹克上掉落的速率。结果表明，可以从合适的表面上捡起大量玻璃碎片。随后发现，用力抓住一件不易留住碎片的夹克会将很大一部分玻璃碎片从手上转移到夹克上。在进行的九次测试中的七次中，在手部与碎玻璃最初接触60分钟后，从夹克上回收了十个或更多的玻璃碎片。在其中三次测试中回收了二十多个碎片。因此，在排除间接转移作为所回收“匹配”玻璃的一种可能解释之前，如有可能且合适，应仔细考虑案件的全部情况。即使对于不易留住碎片的衣物也是如此。
