Abstract：
Homicide, particularly where a body has been concealed, is uniquely challenging for investigators to estimate the time of occurrence due to the methods employed by perpetrators to hide the body or its constituent parts from detection. The regularity of necrophagous insect lifecycles to determine minimum post-mortem interval (minPMI) is widely employed but remains an unreliable technique if used without a clear understanding of the factors that affect insect access and oviposition behaviour to concealed remains. The purpose of this study was to investigate the effect of wrapping body parts on fly colonisation and implications for minPMI calculations. Field studies were carried out using four treatments of pork (as surrogate body parts), in five replicates, one unwrapped, the other three wrapped in either a black plastic sack, a small-zipped wash bag (to simulate a suitcase), or a plastic sack further placed in a wash bag. Over a 48-h period all the methods of wrapping significantly disrupted the host-finding process of blowflies to dismembered carcasses, with a delay of initial contact and oviposition of 30+h (dependant on wrapping) and even more in wet conditions (48+ h). Egg numbers were also reduced by as much as 99.1% on wrapped samples compared to unwrapped. These new findings highlight the importance of applying adjustments to minPMI calculations when encountering wrapped remains. Advances in the accuracy of minPMI calculations will prevent the waste of valuable police time and resources and better focus the search for witnesses and suspects in homicide investigations.
摘要：
凶杀案,特别是在尸体被隐藏的地方，对于调查人员来说，由于犯罪者使用隐藏身体或其组成部分的方法来进行检测，因此估计发生的时间具有独特的挑战性。用于确定最小验尸间隔（minPMI）的食尸昆虫生命周期的规律性得到了广泛采用，但如果在没有清楚了解影响昆虫进入和产卵行为的因素的情况下使用，则仍然是一种不可靠的技术。这项研究的目的是研究包裹身体部位对苍蝇定植的影响以及对minPMI计算的影响。使用四种处理猪肉（作为替代身体部位）进行了实地研究，在五次重复中，一个解开，另外三个包裹在黑色塑料袋中，一个小拉链洗衣袋（模拟手提箱），或进一步放置在洗漱袋中的塑料袋。在48小时的时间内，所有包裹方法都显着破坏了蝇蝇到肢解尸体的宿主发现过程，初始接触和产卵延迟30+h（取决于包裹），在潮湿条件下（48+h）甚至更多。与未包裹相比，包裹样品的鸡蛋数量也减少了99.1％。这些新发现凸显了在遇到包裹残存时对minPMI计算进行调整的重要性。minPMI计算准确性的进步将防止浪费宝贵的警察时间和资源，并更好地集中寻找凶杀案调查中的证人和嫌疑人。
