What happened before the run over? Morphometric 3D reconstruction

Forensic exploitation of patterned injuries: Promoting structured analysis as an early assessment for comparison process

Practice at our Center shows that approach using 3D surface imaging for morphometric comparison of patterned injuries does not always lead to accurate conclusions. We decided to evaluate whether a selection protocol focused on analysis phase could enable us to form an early assessment of the outcome of a comparison process, and then to select lesions likely to lead to a probative conclusion. 23 blunt objects were used to create 65 patterned injuries on an experimental model simulating human skin. A blinded analysis and a comparison were conducted on photographs and 3D models of the lesions. Statement of analysis phase was consistent with comparison results in most cases, enabling correct identification of the responsible object or at least keeping it as possibly responsible among 2 to 3 objects. Our protocol has been demonstrated to improve ability to exploit patterned injuries from surface imaging, despite certain limiting factors.

3D reconstruction of events: Search for a spatial correlation between injuries and the geometry of the body discovery site

The aim of the study was to assess the usefulness of analysing visual material in a 3D environment when examining spatial interrelations between the incident participants, tools, and space surrounding the incident site. Such analysis may provide information about the trauma mechanism, which may lead to the determination of probable events. This paper points to the potential of conducting research under 3D environment conditions on the example of a specific criminal incident-a suspected homicide. The aim of the study was to identify possible circumstances of the events with particular emphasis on the mechanism of death and the involvement of third parties. It was performed a comprehensive 3D reconstruction of the elements of the incident using different sources and forms of evidence, and consequently also different imaging, analysis, and synthesis technologies. The resulting 3D reconstruction and animation of the possible events serve to verify the investigative hypotheses. The paper combines a technical description of the research methodology with a forensic commentary, which ultimately creates an integral synthesis of the medicolegal assessment for trial purposes, while presenting the effectiveness of the research methods used. To sum up, the paper presents an experiment carried out under virtual conditions, impossible to execute under real conditions but critical for trial case analysis.

The Precision, Inter-Rater Reliability, and Accuracy of a Handheld Scanner Equipped with a Light Detection and Ranging Sensor in Measuring Parts of the Body-A Preliminary Validation Study

BACKGROUND

Anthropometric measurements play a crucial role in medico-legal practices. Actually, several scanning technologies are employed in post-mortem investigations for forensic anthropological measurements. This study aims to evaluate the precision, inter-rater reliability, and accuracy of a handheld scanner in measuring various body parts.

METHODS

Three independent raters measured seven longitudinal distances using an iPad Pro equipped with a LiDAR sensor and specific software. These measurements were statistically compared to manual measurements conducted by an operator using a laser level and a meterstick (considered the gold standard).

RESULTS

The Friedman test revealed minimal intra-rater variability in digital measurements. Inter-rater variability analysis yielded an ICC = 1, signifying high agreement among the three independent raters. Additionally, the accuracy of digital measurements displayed errors below 1.5%.

CONCLUSIONS

Preliminary findings demonstrate that the pairing of LiDAR technology with the Polycam app (ver. 3.2.11) and subsequent digital measurements with the MeshLab software (ver. 2022.02) exhibits high precision, inter-rater agreement, and accuracy. Handheld scanners show potential in forensic anthropology due to their simplicity, affordability, and portability. However, further validation studies under real-world conditions are essential to establish the reliability and effectiveness of handheld scanners in medico-legal settings.

Beyond the visible spectrum - applying 3D multispectral full-body imaging to the VirtoScan system

Multispectral photography offers a wide range of applications for forensic investigations. It is commonly used to detect latent evidence and to enhance the visibility of findings. Additionally, three-dimensional (3D) full-body documentation has become much easier and more affordable in recent years. However, the benefits of performing 3D imaging beyond the visible (VIS) spectrum are not well known, and the technique has not been widely used in forensic medical investigations. A multicamera setup was used to employ multispectral photogrammetry between 365 and 960 nm in postmortem investigations. The multicamera setup included four modified digital cameras, ultraviolet (UV) and near-infrared (NIR) light sources and supplemental lens filters. Full-body documentation was performed in conjunction with the use of a medical X-ray computed tomography (CT) scanner to automate the imaging procedure. Textured 3D models based on multispectral datasets from four example cases were reconstructed successfully. The level of detail and overall quality of the 3D reconstructions varied depending on the spectral range of the image data. Generally, the NIR datasets showed enhanced visibility of vein patterns and specific injuries, whereas the UV-induced datasets highlighted foreign substances on the skin. Three-dimensional multispectral full-body imaging enables the detection of latent evidence that is invisible to the naked eye and allows visualization, documentation and analysis of evidence beyond the VIS spectrum.

High-quality Digital 3D Reconstruction of Microscopic Findings in Forensic Pathology: The Terminal Pathway of a Heart Stab Wound

High-quality digital three-dimensional (3D) reconstructions of microscopic findings have been used in anatomical and histopathologic research, but their use in forensic pathology may also be of interest. This paper presents an application of these methods to better characterize the pathway of a stab wound of the anterior surface of the heart in a case of suicide. A portion of the heart wall including the stab wound was serially sectioned for microscopic analysis along the full extent of the wound. Histologic sections were digitally acquired, and a 3D reconstruction was created with ImageJ software for 3D computer graphics. This showed a full-thickness wound path extending to the endocardial surface of the left ventricle, curvilinear in appearance. After correction for shrinkage, 3D reconstruction allowed estimation of the dimensions of the myocardial injury and comparison of the appearance of the wound with the suspected knife used. The curvilinear appearance was considered to reflect injury during myocardial contraction. Complete microscopic sectioning and 3D reconstruction may allow virtual sectioning through various orientations and also provide useful forensic information for selected injuries.

Lying on the Road Before Being Run Over: Vehicular Manslaughter, Suicide, or Accident? Two Case Reports and Literature Review

We present two apparent hit-and-run cases where two women were run over. The vehicles involved were subsequently traced and their owners charged with manslaughter. Autopsy evidence, scientific investigation of the scene and circumstances of the deaths, technical inspection of the vehicles, and DNA analysis strongly suggested that both victims were lying on the road before the accident. Case 1 was a suicide. In Case 2, the victim had fallen to the ground following acute alcohol intoxication. Victimological analysis was pivotal in reconstructing the dynamics of the events. We suggest that a hit-and-run fatality should not be regarded as a manslaughter case until each piece of evidence has been carefully considered. We also propose an interdisciplinary method of reconstructing run over occurrences based on the following three steps: (i) identify whether there was a primary impact when the victim was in an upright position; (ii) identify victim drug/alcohol intoxication and/or presence of acute or chronic disease or injury, which may have contributed to the impact; and (iii) consider suicide intent.