Latent fingermark detection can become increasingly difficult in the weeks following deposition, due to chemical and physical changes influenced by environment. There has been increased research interest into ageing mechanisms of fingermark residue, however these studies have typically been conducted in dry, indoors conditions. Less information is available regarding degradation processes that may occur in scenarios involving water and the potential longevity of porous substrates under such conditions. A pilot study was conducted to investigate the performances of Oil Red O (ORO) and physical developer (PD) on samples submerged in different aquatic environments in a laboratory setting. Charged fingermarks from three donors were deposited on copy paper and immersed in either salt water or freshwater; still or with water flow. Samples were treated at multiple intervals (1, 12, 20 and 40 days) after submersion. Results showed that high quality of development could be achieved up to 40 days after immersion. The overall performances of ORO and PD were generally unaffected in the early stages of the study. Physical and chemical degradation of both latent residue and substrate were observed, which were increased by salt and water movement. While PD appeared to be less affected by potential chemical changes, it was less effective than ORO due to substrate degradation in moving salt water. These results present the first steps towards better understanding the practical effects of degradation processes specific to fingermarks on porous substrates underwater.
This study investigated the use of 3D postmortem computed tomography (PMCT) images of the first and second ribs for sex estimation in a Japanese population. Sex estimation models using conventional discriminant analysis and ten machine learning algorithms including logistic regression (LR), Naive Bayes (NB), K-Nearest Neighbors (KNN), decision tree (DT), random forest (RF), support vector machine (SVM), linear discriminant analysis (LDA), quadratic discriminant analysis (QDA), artificial neural network (ANN), and extra tree (ET), were achieved from PMCT measurements of the first and second rib and the accuracy of models were compared. The results showed that ML algorithms, particularly LR, outperformed discriminant analysis, achieving an accuracy of 83.6 % compared to 79.1 % for stepwise discriminant analysis. This study highlights the potential of 3D PMCT and ML for accurate sex estimation in forensic anthropology.
A man in his 60 s, who had experienced sustained abdominal pain intermittently for three years, lost consciousness and was transferred to an emergency hospital, where he was pronounced dead. In the forensic autopsy, a giant bladder stone measuring 6.5 × 6.0 × 4.0 cm was found adhering to an aluminum eyeliner that penetrated the anterior wall of his rectum. This might have induced pyelonephritis in the left kidney, resulting in sepsis. The deceased may have inserted the eyeliner for sexual stimulation. However, the eyeliner did not injure the peritoneum and no peritonitis occurred, which probably prevented acute sepsis immediately after insertion. The exact time of penetration was undetermined; however, the rectal foreign body may have been retained for three years. This case suggests that sexual activity should be considered a possible manner of death, even if it took place several years previously.