Cranfield Forensic Institute, Cranfield University, Shrivenham, Swindon, SN6 8LA, United Kingdom.
Cranfield Forensic Institute, Cranfield University, Shrivenham, Swindon, SN6 8LA, United Kingdom.
J Forensic Leg Med. 2022 Jan;85:102292. doi: 10.1016/j.jflm.2021.102292. Epub 2021 Nov 24.
Forensic experts rely on scene and/or autopsy photographs to estimate the post-mortem interval (PMI) when an in-situ assessment of decomposition is unfeasible. The degree of decomposition may vary between the scene and autopsy, which importantly could affect estimations of the unknown PMI in forensic casework. This study aimed to investigate decomposition variability between the scene and autopsy and assess the subsequent effect on the accuracy of PMI estimations. Scene and autopsy photographs from 94 cases with known PMI were used from the Allegheny County Office of the Medical Examiner in Pittsburgh, United States. The total decomposition scoring (TDS) method measured the overall decomposition level, and 28 markers of decomposition were recorded as a percentage of the total body surface area (TBSA). In 60% of cases the TDS had increased at autopsy causing significant overestimations of the autopsy PMI and 86% of decomposition markers varied between the scene and autopsy. Decomposition progressed during mortuary time lags (MTL) of 3-44 h, where bodies were stored in a pre-autopsy refrigerator at 4 °C, suggesting that refrigeration may not always delay decomposition. This research also assisted in validating photographs as a proxy for real-time decomposition assessments. While the autopsy photographs conferred higher quality than the scene photographs, the scene photographs produced more accurate PMI estimations. Forensic experts should exhibit caution when estimating the PMI from autopsy photographs alone, as they may not accurately reflect scene decomposition. To prevent misinterpretation of the PMI estimation, both scene and autopsy photographs should always be requested.
法医专家依靠现场和/或尸检照片来估算死后间隔时间（PMI），当无法对现场的分解情况进行原位评估时。现场和尸检的分解程度可能有所不同，这对法医工作中对未知 PMI 的估计很重要。本研究旨在调查现场和尸检之间的分解差异，并评估其对 PMI 估计准确性的后续影响。本研究使用了来自美国匹兹堡阿勒格尼县法医办公室的 94 例已知 PMI 的案例的现场和尸检照片。总分解评分（TDS）方法测量了整体分解水平，并记录了 28 个分解标记，占身体总表面积（TBSA）的百分比。在 60%的病例中，尸检 TDS 增加，导致尸检 PMI 高估，86%的分解标记在现场和尸检之间存在差异。分解在停尸房时间滞后（MTL）的 3-44 小时内进行，在 4°C的预尸检冰箱中储存尸体，这表明冷藏并不总是会延迟分解。本研究还协助验证了照片作为实时分解评估的替代物。虽然尸检照片比现场照片质量更高，但现场照片产生的 PMI 估计更准确。法医专家在仅从尸检照片估计 PMI 时应谨慎行事，因为它们可能无法准确反映现场的分解情况。为了防止 PMI 估计的误解，应始终要求提供现场和尸检照片。
