Samie Lydie, Champod Christophe, Delémont Séverine, Basset Patrick, Hicks Tacha, Castella Vincent
Forensic Genetics Unit, University Center of Legal Medicine, Lausanne - Geneva, Lausanne University Hospital and University of Lausanne, Ch. de la Vulliette 4, 1000 Lausanne 25, Switzerland.
Faculty of Law, Criminal Justice and Public Administration, School of Criminal Justice, University of Lausanne, Lausanne-Dorigny, Switzerland.
Forensic Sci Int. 2022 Feb;331:111174. doi: 10.1016/j.forsciint.2022.111174. Epub 2022 Jan 4.
Chemical and staining methods, immunochromatography, spectroscopy, RNA expression or methylation patterns, do not allow to determine the nature of the biological material with certainty. However, to our knowledge, there are few forensic scientists that assess the value of such test results using a probabilistic approach. This is surprising as it would allow account for false positives and false negatives and avoid misleading conclusions. In this paper, we developed three Bayesian Networks (BNs) to assess the presence of blood, saliva and sperm in the recovered material and combine potentially contradictory observations. The approach was successfully tested using 188 traces from proficiency tests. We have implemented an online user-friendly application (https://forensic-genetic.shinyapps.io/BodyFluidsApp/) that allows forensic scientists to assess the value of their results without having to build Bayesian Networks themselves. They can also input their own data, use the application to identify a potential lack of knowledge and report their conclusions regarding the presence of sperm, blood or/and saliva considering uncertainty.
化学和染色方法、免疫色谱法、光谱法、RNA表达或甲基化模式，都无法确定生物材料的性质。然而，据我们所知，很少有法医科学家使用概率方法评估此类测试结果的价值。这令人惊讶，因为这样可以考虑假阳性和假阴性，并避免得出误导性结论。在本文中，我们开发了三个贝叶斯网络（BNs），以评估回收材料中血液、唾液和精子的存在情况，并整合潜在矛盾的观察结果。该方法通过能力验证测试中的188份痕迹样本进行了成功测试。我们开发了一个在线用户友好型应用程序（https://forensic-genetic.shinyapps.io/BodyFluidsApp/），法医科学家无需自己构建贝叶斯网络，就能评估其结果的价值。他们还可以输入自己的数据，使用该应用程序识别潜在的知识不足，并在考虑不确定性的情况下报告关于精子、血液或/和唾液存在情况的结论。
