Abstract：
When reporting results of Gunshot Residue (GSR) analysis from a person suspected to be involved in a recent shooting, most forensic experts only provide the court with the raw results (i.e. the number of GSR particles found) and a disclaimer that a positive finding does not prove that the suspect was involved in a firearm shooting incident whilst a negative finding does not prove that he was not. Probabilistic analysis of the GSR results provides more value to the court, so the present study calculated likelihood ratio (LR) values for finding 0-8 characteristic GSR particles (containing Lead, Barium and Antimony) on a suspect\'s hands, based on the available GSR data from the published literature as well as studies by the authors. Defense propositions, i.e. modes for GSR acquisition other than involvement in a shooting event, were divided into three broad categories: low, medium and heavy background. For each background level and number of GSR particles found, minimal and maximal LR values were calculated. Thus, for each proposition the defense provides for the presence of GSR on the defendant\'s hands, the forensic expert can provide a possible set of minimal and maximal LR values, leaving the court to examine the defendant\'s contention and decide which of the three background modes is more plausible according to the circumstances of the specific case.
摘要：
当报告一名涉嫌参与最近枪击事件的人的枪击残留物(GSR)分析结果时，大多数法医专家仅向法院提供原始结果（即发现的GSR颗粒数量）和免责声明，即肯定的发现不能证明嫌疑人参与了枪支射击事件，而否定的发现不能证明他不是。GSR结果的概率分析为法院提供了更多价值，因此，本研究计算了寻找0-8个特征GSR颗粒(含铅，钡和锑)在嫌疑人的手上，基于已发表文献的GSR数据以及作者的研究。国防命题，即除了参与射击事件之外的GSR采集模式，分为三大类：低，中等和重背景。对于发现的每个背景水平和GSR粒子数量，计算最小和最大LR值.因此，对于每个命题，辩方都规定被告手上有GSR，法医专家可以提供一组可能的最小和最大LR值，由法庭审查被告的论点，并根据具体案件的情况决定三种背景模式中哪一种更合理。
