Guo Hongling, Yao Yifeng, Li Yameng, Wang Ping, Hu Can, Yuan Meiqing, Mei Hongcheng, Zhu Jun
Institute of Forensic Science, Ministry of Public Security of China, Beijing, China.
State Key Laboratory of Systematic and Evolutionary Botany, Institute of Botany, Chinese Academy of Sciences, Beijing, China.
J Forensic Sci. 2022 Mar;67(2):766-774. doi: 10.1111/1556-4029.14921. Epub 2021 Nov 27.
Soil examination can provide useful forensic information about the spatial location and suspect's activities. Many techniques have been applied for soil comparison and provenance determination in criminal investigations. Pollen and diatom identification, which has the potential to provide an independent ecological assessment of soil evidence, is currently underused in forensic soil analysis. This work presents a case study of application of these methods to help criminal investigation in a murder case, which happened in an irrigation ditch in Hunan Province, southern China. Soils from the suspect's clothes, the exact crime scene spot in the irrigation ditch, along the ditch and the reference ditches were collected and analyzed. In addition to the element and mineral analysis, pollen and diatom assemblages were analyzed for further comparison. The statistical methods of hierarchical cluster and cosine similarity analysis were carried out to assist in soil comparison and provenance determination. The results showed that soil on the suspect's clothes had a high probability to share the same source with the soil from the crime scene in the irrigation ditch. The suspect confessed to murder based largely on the soil examination result even without other evidences.
土壤检验可为犯罪现场的空间位置及嫌疑人活动提供有用的法医鉴定信息。在刑事调查中，已有多种技术用于土壤比对和来源判定。花粉和硅藻鉴定有可能对土壤证据进行独立的生态评估，但目前在法医土壤分析中未得到充分利用。本文介绍了一个案例研究，将这些方法应用于一起发生在中国南方湖南省一条灌溉沟渠中的谋杀案的刑事调查。采集了嫌疑人衣物上的土壤、灌溉沟渠中确切犯罪现场位置的土壤、沟渠沿线的土壤以及参考沟渠的土壤并进行分析。除了元素和矿物分析外，还对花粉和硅藻组合进行分析以作进一步比对。采用层次聚类和余弦相似度分析等统计方法辅助土壤比对和来源判定。结果表明，嫌疑人衣物上的土壤很可能与灌溉沟渠中犯罪现场的土壤来源相同。即便没有其他证据，嫌疑人也主要基于土壤检验结果供认了谋杀罪行。
