Crime Scene Investigation Research Articles

Collecting touch DNA from glass surfaces using different sampling solutions and volumes: Immediate and storage effects on genetic STR analysis.

Touch DNA has become increasingly important evidence in todays' forensic casework. However, due to its invisible nature and typically minute amounts of DNA, the collection of biological material from touched objects remains a particular challenge that underscores the importance of the best collection methods for maximum recovery efficiency. So far, swabs moistened with water are often utilized in forensic crime scene investigations for touch DNA sampling, even though an aqueous solution provokes osmosis, endangering the cell's integrity. The aim of the research presented here was to systematically determine whether DNA recovery from touched glass items can be significantly increased by varying swabbing solutions and volumes compared with water-moistened swabs and dry swabbing. A second objective was to investigate the possible effects of storage of swab solutions prior to genetic analysis on DNA yield and profile quality when stored for 3 and 12 months, as is often the case with crime scene samples. Overall, the results indicate that adapting volumes of the sampling solutions had no significant effect on DNA yield, while the detergent-based solutions performed better than water and dry removal, with the SDS reagent yielding statistically significant results. Further, stored samples showed an increase in degradation indices for all solutions tested, but no deterioration in DNA content and profile quality, allowing for unrestricted processing of touch DNA samples stored for at least 12 months. One further finding was a strong intraindividual change in DNA amounts observed over the 23 deposition days which may be related to the donor's menstrual cycle.

Neural network based hyperspectral imaging for substrate independent bloodstain age estimation

Being able to determine the age of a bloodstain can be a key element in a crime scene investigation. Many techniques exploit reflectance spectroscopy because it is very versatile and can be used in the field with ease. However, there are no methods for estimating bloodstain age with adequate uncertainty, and the problem of substrate influence is not yet fully resolved. We develop a hyperspectral imaging based technique for the substrate-independent age estimation of a bloodstain. Once the hyperspectral image is acquired, a neural network model recognizes the pixels belonging to the bloodstain. The reflectance spectra belonging to the bloodstain are then processed by an artificial intelligence model that removes the effect of the substrate on the bloodstain and then estimates its age. The method is trained on bloodstains deposited on 9 different substrates over a time period of 0–385 h obtaining an absolute mean error of 6.9 h over the period considered. Within two days of age, the method achieves a mean absolute error of 1.1 h. The method is finally tested on a new material (i.e., red cardboard) never used to test or validate the neural network models. Also in this case the bloodstain age is identified with the same accuracy.

GAN and MIRNet-Assisted Image Enhancement: A Promising Future in Visual Computing

Abstract: We present an extensive strategy for improving images using deep learning-based techniques, concentrating onsuperresolution (SR) and low-light image improvement utilizing generative adversarial networks (GANs) and misalignment-robust networks (MIRNet), respectively. During the SGAN training phase, a deep convolution neural network learns a complete link between low- and high-resolution pictures. Our approach simultaneously optimises all layers to provide cutting-edge restoration quality and quick speed for practical application. To achieve performance and speed trade-offs, we also investigate alternative network setups andparameter settings.Additionally, we upgrade the overall reconstruction quality by expanding our network to handlethree color channels concurrently. In contrast, MIRNet is utilized for low light image improvement, which has grown in significance as a result of the increased need for trustworthy picture enhancement systems in real-time applicationsincluding autonomous driving, surveillance footage, and crime scene investigations. MIRNet, which may be used for a range of image improving applications.

A holistic approach for the selection of forensic DNA swabs

In the present study, we compared the performance of five different ISO 18385 certified forensic swabs for DNA sampling in practice over a time period of five months. Comparisons were made for DNA profiling success rates, measured as the percentage of CODIS (Combined DNA Index System) suitable profiles as well as for practical suitability during sampling at the scene, measured through a survey among collaborators. More than forty members of our crime scene investigation (CSI) unit took part in the test series and provided structured feedback concerning different aspects of swab handling. A total number of 1094 “touch” DNA samples have been subjected to DNA analysis. Swabs performed significantly different in terms of DNA profiling success rates. We also observed significant differences in DNA extraction efficiency between swabs. The evaluation by the collaborators of various aspects of handling differed significantly between swabs. We can assume that a more convenient handling decreases the risk of contamination or sample mislabelling and increases sampling efficiency and staff satisfaction. Our results demonstrate that the selection of disposable sampling devices such as forensic swabs for DNA sampling should be made based on a holistic approach. To be able to select the best performing swab for a given combination of CSI and DNA laboratory procedures, it might not be sufficient to only perform DNA extraction comparisons and trace sampling under controlled laboratory conditions.

Forensic odontology identification in a case of flash-fire death

Forensic dentistry, or forensic odontology is a great chapter in forensic pathology that focuses on the dental remains of unrecognizable cadavers to perform their recognition. In some cases, dental identification is the only method available to make or refute the identification of a cadaver. During a crime scene investigation, human remains were found in a completely burned-out car. At the external examination, the cadaver was unrecognizable. At complete autopsy, the presence of soot in the airways was ascertained as a vitality marker. A forensic dental examination was performed. Dental photos of a suggested missing man were analyzed and showed the same anatomical dental features as those of the cadaver. The comparison of the orthopantomogram (OPT) obtained ante mortem from the missing person with the one obtained post mortem from the cadaver matched perfectly. Hence, forensic odontology proved valuable to identify the cadaver working in conjunction with forensic pathology and forensic radiology.

Introducing a Rapid DNA Analysis Procedure for Crime Scene Samples Outside of the Laboratory-A Field Experiment.

Technological innovations enable rapid DNA analysis implementation possibilities. Concordantly, rapid DNA devices are being used in practice. However, the effects of implementing rapid DNA technologies in the crime scene investigation procedure have only been evaluated to a limited extent. In this study a field experiment was set up comparing 47 real crime scene cases following a rapid DNA analysis procedure outside of the laboratory (decentral), with 50 cases following the regular DNA analysis procedure at the forensic laboratory. The impact on duration of the investigative process, and on the quality of the analyzed trace results (97 blood and 38 saliva traces) was measured. The results of the study show that the duration of the investigation process has been significantly reduced in cases where the decentral rapid DNA procedure was deployed, compared to cases where the regular procedure was used. Most of the delay in the regular process lies in the procedural steps during the police investigation, not in the DNA analysis, which highlights the importance of an effective work process and having sufficient capacity available. This study also shows that rapid DNA techniques are less sensitive than regular DNA analysis equipment. The device used in this study was only to a limited extent suitable for the analysis of saliva traces secured at the crime scene and can mainly be used for the analysis of visible blood traces with an expected high DNA quantity of a single donor.

Bilgisayarla İşlenen Suçlara Hızlı Müdahale, İnceleme, Analiz ve Raporlama Süreçlerinin Yeni Nesil Adli Bilişim Yöntemleri İle Etkin Yönetimi

Because of the exponential growth in the volume and speed of attack vectors, the rapid growth of computer crimes, the corporate attack surface and the enormous volumes of data, preventing the cyber-attacks has become very difficult. In terms of forensics, classical forensic methods in a traditional approach which include removing the disk, gettng its image and examining the image takes a lot of time with the increasing amount of data so that this situation leads to make quick intervention too difficult against cyber attack and it takes a lot of time. For example, on average, getting an image of harddisk which include 20 terabyte capacity takes 2 days of time. As a solution, with a special tool (Binalyze AIR) that collects only evidentiary documents getting hash of all evidences (Disk Proof, Proof of Memory, Proof of Scanner, Proof of NTFS, Proof of Log, Proof of Network, Proof of Event Logs, Proof of WMI, Proof of Process Execution, etc.) and collects only the documents that have the quality of evidence, thus this process can be completed in a very short time. It provides effective management of crime scene investigation and fast response to crimes committed by computer, investigation, analysis and reporting processes blocked with traditional forensic methods and offers an innovative solution to the scientific literature. In summary, in this study, the results obtained by using modern forensic techniques (Binalyze AIR and Binalyze Tactical software) are presented in comparison with classical forensic methods.

Organization and Tactics Crime Scene Investigation

The organization of crime scene investigation carried out by police officers in Ukraine was considered and analyzed. Based on the analysis, it was determined that it is advisable to conduct an inspection of the scene of the incident by an investigative team, which should include a group of several specialists who perform the main work of identifying, fixing, extracting, and examining material objects.

과학수사관의 외상후스트레스 반응에 대한 질적 연구

This study aims to examine the posttraumatic stress response characteristics experienced by crime scene investigators after conducting crime scene identification work, and their personal coping efforts. Additionally, the study aims to identify organizational support measures desired by crime scene investigators through qualitative research, in order to provide differentiated support. A focused group interview was conducted in July 2022 with nine crime scene investigators, and additional information was supplemented through phone interviews when necessary. Six main themes emerged: painful scenes, unstable daily routines, challenging organizational aspects, personal coping efforts, supportive colleagues and seniors, and psychological support systems. Based on the findings, a psychological support system for the psychological pain of crime scene investigators was discussed, divided into stages of intervention.

Retsmedicinske findestedsundersøgelser

AbstractDuring the years 2000 to 2020 the Department of Forensic Medicine at the University of Southern Denmark performed 293 medical crime scene investigations in Southern Denmark involving 320 deceased (200 men). The medical examiner was called out in homicides (24%), suspicious cases (58%), fire related deaths (15%) and bone findings (2%). The medical examiner was responsible for the medical examination of corpses in cooperation with the crime scene technicians. The goal was to determine the cause of death, the manner and mechanism of death, and the time of death. Most were autopsied after the crime scene investigation. The scene was considered suspicious if displacedor broken furniture, or bloodstains, were found. Actions by alcohol or drug intoxicated individuals may resemble a crime scene. Blood stains can arise from natural causes. Suicide by stabbing or shooting may give rise to a suspicious scene, as may deaths during autoerotic procedures and deaths due to hypothermia. Most crime scenes were indoors, but a quarter occurred outside. The deceased included a high proportion of individuals with chronic alcoholism (36%) and many suffered from psychiatric disease (23%). Based on autopsy, manner of death was determined to have been homicide (30%), accident (27%), suicide (18%), natural death (14%) and unknown causes (6%). 5% was not autopsied.The pattern of lesions are important in determining the mechanism of death, but must always be viewed in relation to findings at the scene and the deceased’s history. Medical crime scene investigation underwent improvements during the period, most notably the introduction of DNA-trace analysis. Photo and video documentation also improved.Photogrammetry and the use of drones are being introduced.

An evaluation of measurement uncertainty of trajectory angles using a 3D laser scanner.

Measuring trajectory angles of bullet defects at a crime scene is an important part of crime scene investigation as these angles can be used for shooting incident reconstructions. The Washington State Patrol Crime Scene Response Team (WSP CSRT) had a desire to report and use measured trajectory angles. To report quantitative measurements, a statement of uncertainty for the measurement must also be reported due to an accreditation requirement through the ANSI National Accreditation Board (ANAB), through which the WSP CSRT is accredited. This evaluation examined the measurement uncertainty of the 3D laser scanning method that the WSP CSRT utilizes for measuring the vertical and azimuth angles from trajectory rods fitted to bullet defects. Three studies were performed which examined the variation of vertical and azimuth angle measurements from trajectory rods on flat surfaces, the variation of azimuth angle measurements from a trajectory rod on a curved surface, and a traceability study with known vertical and azimuth angle measurements. Seven common substrates were selected as target materials and were shot with 9 mm Luger and 0.45 Auto caliber bullets. A vehicle with one bullet defect was utilized for the curved surface study. The WSP's current fleet of Trimble X7 3D laser scanners, the WSP Criminal Investigation Division (CID) Detectives who operate these scanners, and the Forensic Scientists responsible for trajectory rod placement and angle measurements were utilized. An overall measurement uncertainty of +/- 2.6 degrees at an approximate 95% confidence interval was determined for all trajectory angles measured from trajectory rods.

Assessment of Forensic Medical Expert’s Involvement in Primary Crime Scene Investigation in Nairobi

It is of great importance to include Forensic Medical Experts (FMEs) in Primary Crime Scene (PCS) investigation team especially in murder, rape and defilement in investigation framework. The criminal justice system in Kenya has not been effective due to the shortage of FMEs as well as the poor specialization among forensic experts and police officers in implementing Medico-legal services within the country. This research sought to assess the need to involve FMEs in PCS investigation in Starehe sub-county, which comprises of five stations, for the purpose of improving the quality of criminal investigation in the country. A systematic random sampling technique of case files brought back from court was used. The sample size was calculated by dividing the entire case files by interval. There were one hundred and thirty-five (135) case files numbered from one to one hundred and thirty-five (135), then picked at an interval of two from a random number. Sixty-seven (67) case files were sampled, studied and analyzed. Three hypotheses were developed to be tested. The main objective was to assess forensic medical expert’s involvement in PCS investigation in starehe police division, Nairobi County, Kenya. Data analysis was done using SPSS and presented with tables, and narrative. From the tested hypothesis we were able to discover that the FMEs in Kenya are not well trained and professional in the use of SOPs for collecting forensic evidence at PCS H1 (p=0.754); the Kenyan criminal justice system framework does not involve FMEs at all primary stages of investigations H2 (p=0.878); Cases in Kenyan courts are not very successful without the use of FMEs H3 (p=0.247). Involvement of the FMEs in primary crime scenes investigation ensures that there is adequate and sufficient evidence to prosecute criminals convicted of such criminal acts. Cases without forensic evidence component failed to secure a conviction indicating that their absence impacts the quality of evidence submitted to present a sound case to prosecute offenders. FMEs should respond alongside police crime scene investigators and be linked to crime scenes at all stages of investigation to collect forensic evidence to identify suspects responsible for committing criminal activities at the PCS. Forensic evidence should be presented by a qualified professional who complies with standards that enhance efficiency and fairness. The forensic medical evidence at the primary crime scene is best armed with skills, knowledge and tools that are required to aid the investigators to make maximum use of scanty resources available with regard to collection and analysis of biological and chemical evidence. There should be clearer guidelines on the steps to follow in regard to evidence collection. The results of this study will be used by policy makers and health care providers to improve forensic evidence gathering for better and successful prosecution.

Contamination of digital evidence: Understanding an underexposed risk

The dangers of contamination have received considerable attention in the literature regarding the investigation of physical crime scenes and physical evidence. The understanding of contamination in the context of digital evidence appears to be much less understood. Based on experiences from the field of physical evidence, we develop a generalized definition of contamination that also covers digital evidence, namely the “inadvertent transfer of traits to an object of relevance at any point in the forensic process”. We illustrate the definition by presenting several examples and counterexamples for contamination of digital evidence. By addressing the specifics of digital evidence in this context, we argue that our definition can be useful to understand the risks arising through contamination in this domain.

A prototype autonomous robot for underwater crime scene investigation and emergency response

AbstractUnderwater crime scene investigation and emergency response are tasks typically carried out by divers constituting part of a specialist team. Operating in such dynamic environments, often with poor visibility and risk of concealed hazards, can be time consuming and dangerous. Autonomous uncrewed vessels with underwater acoustic imaging sensors have been used for similar purposes in other fields (e.g., hydrography, naval mine countermeasures [MCMS], etc.) but have not been adopted in this specific application domain. The Police Robot for Inspection and Mapping of underwater Evidence (PRIME) is an autonomous uncrewed surface vessel that is being developed for this purpose. It is a novel application of existing robotic technology that is intended to be used within an end‐to‐end police and emergency underwater search process. It aims to enhance the effectiveness, efficiency, and safety of divers by autonomously locating and highlighting target objects or regions of interest, as well as benign regions, thereby reducing their time spent underwater. Side‐scan imaging sonars are used to sense the underwater environment using techniques leveraged from the similar application domain of naval MCMs. The system autonomously generates actionable intelligence in the form of simplified coverage and anomaly maps for easy interpretation by the dive team. These are communicated to shore in real‐time and georeferenced on satellite maps. This paper details the PRIME system prototype and presents results from initial field experimentation. The prototype has been operated in various urban, shallow‐water environments. The experimental results shown here were collected in Bristol Harbour (the UK) with a water depth of approximately 5 m. In the experiment, a clothed mannequin resembling a human body was deployed on the muddy floor. Autonomous searches were executed and the body was detected successfully as an anomaly against the background, illustrating the feasibility and viability of the system as an autonomous robotic aid for locating missing persons in a representative, unstructured, and dynamic real‐world environment.

Single-cell transcriptome sequencing allows genetic separation, characterization and identification of individuals in multi-person biological mixtures

Identifying individuals from biological mixtures to which they contributed is highly relevant in crime scene investigation and various biomedical research fields, but despite previous attempts, remains nearly impossible. Here we investigated the potential of using single-cell transcriptome sequencing (scRNA-seq), coupled with a dedicated bioinformatics pipeline (De-goulash), to solve this long-standing problem. We developed a novel approach and tested it with scRNA-seq data that we de-novo generated from multi-person blood mixtures, and also in-silico mixtures we assembled from public single individual scRNA-seq datasets, involving different numbers, ratios, and bio-geographic ancestries of contributors. For all 2 up to 9-person balanced and imbalanced blood mixtures with ratios up to 1:60, we achieved a clear single-cell separation according to the contributing individuals. For all separated mixture contributors, sex and bio-geographic ancestry (maternal, paternal, and bi-parental) were correctly determined. All separated contributors were correctly individually identified with court-acceptable statistical certainty using de-novo generated whole exome sequencing reference data. In this proof-of-concept study, we demonstrate the feasibility of single-cell approaches to deconvolute biological mixtures and subsequently genetically characterise, and individually identify the separated mixture contributors. With further optimisation and implementation, this approach may eventually allow moving to challenging biological mixtures, including those found at crime scenes.

IPPASOS: The first digital forensic information system in Greece.

This article describes the first digital clinical information system tailored to support the operational needs of a forensic unit in Greece and to maintain its archives. The development of our system was initiated towards the end of 2018, as a close collaboration between the Medical School of the University of Crete and the Forensic Medicine Unit of the University Hospital of Heraklion, Crete, where forensic pathologists assumed active roles during the specification and testing of the system. The final prototype of the system was able to manage the life cycle of any forensic case by allowing users to create new records, assign them to forensic pathologists, upload reports, multimedia and any required files; mark the end of processing, issue certificates or appropriate legal documents, produce reports and generate statistics. For the first 4years of digitised data (2017-2021), the system recorded 2936 forensic examinations categorised as 106 crime scene investigations, 259 external examinations, 912 autopsies, 102 post-mortem CT examinations, 804 histological examinations, 116 clinical examinations, 12 anthropological examinations and 625 embalmings. This research represents the first systematic effort to record forensic cases through a digital clinical information system in Greece, and to demonstrate its effectiveness, daily usability and vast potential for data extraction and for future research.

“Blood, Bucks and Bias”: Reliability and biasability of crime scene investigators’ selection and prioritization of blood traces

When crime scene investigators (CSIs) encounter crime scenes with large volumes of blood, some selection and prioritization is often needed, and this will impact on what blood is and is not available for forensic analysis. What factors influence CSIs decision making process is largely unknown. This study examines the effects of awareness of limited resources and irrelevant contextual case information indicating either a homicide or a suicide on CSIs collection of blood traces. To this end, two scenario-based experiments with CSIs and novices were conducted. Overall, the results suggest that even when CSIs decisions are made under identical conditions, their trace selection varies both when it comes to numbers and locations. Furthermore, awareness of limited resources made CSIs collect fewer traces and their selections also varied following the contextual case information, showing similarities and differences with novices. Since blood traces can be used to establish both activity and identity the findings can have important implications for the subsequent investigation as well as trial.

Discrimination of smokers and nonsmokers based on the analysis of fingermarks for forensic purposes

For decades, the unique characteristic ridge pattern of a fingerprint (FP) has been used as a mainstay for human individualization. Most recently, vibrational spectroscopic analysis of fingermark (FM) has attracted a substantial amount of attention in providing intelligence on personal traits. Particularly, extracting phenotypical information such as age and sex can be significantly beneficial in criminal investigation. However, chemical profiling of FMs using vibrational spectroscopy has been limited to age and sex determination, while other significant traits can also aid in narrowing down the suspect pool. In the current proof-of-concept study, attenuated total reflection Fourier transform-infrared (ATR-FTIR) spectroscopy combined with partial least squares-discriminant analysis (PLS-DA) have been employed for determining smoker from non-smoker donors from their FM residues. Genetic algorithm (GA) was applied to improve the discrimination rate of the developed model by selecting regions that are significant for the distinguish between the two classes. A subject wise leave-one-out cross-validation (LOOCV) was initially used to evaluate the performance of the binary PLSDA classifier for each donor. The binary model showed 84% correct classification at spectral level and 92% correct classification at donor level in subject wise LOOCV. In addition, receiver operating characteristic (ROC) curve analysis was constructed to establish a threshold for differentiating between the smoker and non-smoker FMs, this resulted in 100% accuracy at a donor level for external validation test. This preliminary study shows a great promise for identifying smoker donors from non-smoker individuals based on chemical analysis of FM residues. After fully developed, we believe the method will offer significant potential for real crime scene investigation due to its simplicity, non-destructive nature and its prospective for in-field analysis.

Extent of Forensic Practices of Police Investigators: A Basis for Enhancement Plan

In criminal investigations, the Directorate for Investigation and Detective Management – Police investigators are required by Philippine National Police orders to conduct forensic science-based crime scene investigations. In order to ensure that every government employee adheres to the accepted belief that public office is a public trust, it is challenging to assess the work of police detectives performing crime scene investigations using forensic technology. This essential value of forensic science in police investigations is undeniable. This study discusses the scope of police forensic methods in ballistics, photography, and dactyloscopy, specifically in the Province of Antique. These issues regarding the scope of practices in conducting investigations and forensic examinations are expressed via a survey questionnaire and a series of statistical tests. In addition, the report outlines the difficulties experienced by these Philippine National Police investigators. The results of the study found that police investigators had a high level of forensic experience with ballistics and photography. Further, results revealed low level of forensic experience with dactyloscopy.. Therefore, Police investigators, among many solutions, may consider the following to be of great help: 1-attending relevant seminars and trainings involving dactyloscopy, and 2- specifying budget allocation for lacking equipment.

Development of a Dundee Ground Truth imaging protocol for recording indoor crime scenes to facilitate virtual reality reconstruction

Early and accurate visualisation of a crime scene is highly desirable such that a rapid, agile, and informed decision-making process can be undertaken by an investigative team. We present a new standard operating procedure for imaging an indoor scene using DSLR cameras conventionally used by crime scene investigators and examiners. The standard operating procedure (SOP) enables the systematic photography of indoor spaces in such a way that the Structure from Motion (SfM) photogrammetry technique can be implemented, allowing the scene to be recreated in Virtual Reality (VR). To demonstrate the method’s validity, we compare two VR-rendered representations of an example scene using (a) photographs taken by an experienced crime scene examiner using a conventional photographic method and (b) photographs taken by a novice photographer following the developed SOP.