Forensic Science Department, University of New Haven, Henry C. Lee College of Criminal Justice and Forensic Science, West Haven, Connecticut, USA.
J Forensic Sci. 2022 Nov;67(6):2444-2452. doi: 10.1111/1556-4029.15138. Epub 2022 Sep 19.
Latent fingermark ridge patterns result from imprinting sweat secretions onto receiving surfaces. However, little is known about the loss of skin moisture between immediate consecutive depositions and its effects on the visual quality of ridges and their degradation over time. In practice, it is recurrently assumed that the first touch should contain the most residue and, therefore, display the highest ridge quality. Also, it is expected to observe a gradual decrease in the quantity of residue deposited and, in turn, in the clarity of ridges. In this study, a total of 480 fingermarks were obtained from 20 donors, 10 males and 10 females, to assess the pattern loss of ridge quality across six successive impressions in a depletion series. Black magnetic powder (BMP) was utilized to visualize and photograph fingermarks on glass microscope slides. After image standardization, Quality Scores (QS) as well as metrics on ridge clarity were obtained from the FBI's Universal Latent Workstation (ULW). Data analyses revealed a significant drop in ridge quality over the six consecutive depositions, but notably after deposition four. No differences in ridge clarity between sexes were detected within the first three depositions although an effect was noted beyond this point. ULW proved to be an excellent and sensitive tool in detecting minute changes in ridge quality across the depletion series. These results may contribute in determining the chronological order of events and support further research in estimating time-since-deposition.
潜在指印纹线图案是由汗液分泌物在接受表面上留下的印痕形成的。然而，对于连续两次印痕之间皮肤水分的丧失及其对纹线视觉质量的影响，以及纹线随时间的退化过程，我们知之甚少。在实践中，人们反复假设第一次触摸应该包含最多的残留物，因此应该显示出最高的纹线质量。同时，预计会观察到残留物沉积量的逐渐减少，从而导致纹线清晰度的降低。在这项研究中，我们从 20 名捐赠者（10 名男性和 10 名女性）中总共获得了 480 个指印，以评估在消耗系列中的六个连续印痕中纹线质量的损失模式。我们使用黑色磁性粉末（BMP）来可视化和拍摄显微镜载玻片上的指印。在图像标准化后，我们从 FBI 的通用潜在工作站（ULW）中获得了质量分数（QS）以及纹线清晰度的度量。数据分析显示，在六个连续的印痕中，纹线质量显著下降，但在第四个印痕之后尤为明显。在前三组印痕中，我们没有发现性别对纹线清晰度的差异，但在这之后就有了这种效应。ULW 被证明是一种检测在消耗系列中纹线质量细微变化的极好和敏感的工具。这些结果可能有助于确定事件的时间顺序，并支持进一步研究估计时间。
