Crime Scene Evidence Research Articles

Regarding the Pain of Indigenous Others

Cities are real, physical, material concentrations of human activities and built environments, but they are also portals that allow and require unique ways of perceiving relations across space and time. Photography, especially the genre of seductive urban landscape views so often deployed by airlines, realtors, and city boosters, distorts our perceptions of space-time. These distortions are particularly serious in the unique configuration of Indigeneity and transnationalization that constitutes the lands presently known as Canada and British Columbia. Drawing inspiration from Sontag's dark but essential Regarding the Pain of Others, and focusing on the Vancouver global city region, this article seeks to develop critical captions for urban landscape views as what Eugène Atget portrayed as crime-scene evidence.

Dansyl fluorophore functionalized hierarchically structured mesoporous silica nanoparticles as novel latent fingerprint development agents.

A nanostructured hybrid material based on mesoporous silica nanoparticles (MCM-41) functionalized with chitosan and a fluorescent dye (dansylglycine), designated MCM-41@Ch@DnsGly, was synthesized and characterized with a view to its application for the visualization of latent fingerprints. These nanoparticles were applied as latent fingerprint developers for marks on surfaces of diverse chemical composition, topography, optical characteristics, and spatially variant nature, typical of forensically challenging evidence. For quality assessment of the enhanced fingermarks, the developed images were analyzed holistically using the UK Home Office scale, forensic protocols and, in terms of their constituent features (minutiae), using forensic software. Across a substantive collection of marks deposited on chemically diverse surfaces and subject to complex environmental and temporal histories, 94% of the enhanced images presented sufficient minutiae for comparison with model dactyloscopy images. This novel nanomaterial presents enhanced performance with significant promise for superior exploitation by forensic practitioners in the acquisition and analysis of crime scene evidence.

Role of Nanotechnology in Forensic Medicine to Solve Medico-legal Case Work in Pakistan - A Review Study

Background: Nanotechnology is relatively a new emerging field of Forensic Science and is being used to solve many medico-legal cases all over the world. Some of its use is the most prevalent in biomedical science, material science, biological indicators, food science, Trace Evidence, real-time crime scenes, and terrorist attacks as a nanomaterial to the medico-legal investigations. It is now utilized in the medico-legal casework in Pakistan in Forensic Medicine. Aim: To analyze and compare the forensic value of nanotechnology and methods used to solve the medico-legal investigations relating to nanomaterials in Forensic medicine in Pakistan, Pakistan. Method: This is a review study focusing on the currently available data in research articles all over the world and in Pakistan about the use of nano-material in medico-legal casework for slaving medico-legal investigations in Pakistan. Extensive research is being conducted on the use of nanomaterials. Various analysis methods for nanomaterials, both old and new, have been gathered from previous research and compared. The statistical significance of their use as forensic evidence in criminal investigations and medico-legal cases has been analyzed in the field of Forensic Medicine. Results: The field of nanotechnology plays a crucial role in forensic investigations. This is supported by numerous publications both globally and in Pakistan. Nanomaterials have been instrumental in solving many forensic cases by leveraging advanced technology and high-tech tools. The Pakistan Forensic Science Agency in Lahore (PFSA) has effectively utilized nanomaterials in DNA analysis and various serological tests. Notably, nanomaterials have greatly aided in identifying crime scene evidence through the use of Polymerase Chain Reactions (PCR). Practical Implication: New nanotechnologies are being utilized in DNA fingerprinting to solve medico-legal cases in forensic investigations. Advancements include the use of capillary electrophoresis, nano-gold, nano-silver, and nanoparticles of titanium dioxide (TiO2) combined with SEM, TEM, and FTIR(56). Currently, there are ongoing developments to create new nano-probes, nano-devices, and nano-chips to combat the threat of terrorism in Pakistan. Conclusion: Nanotechnology is being very extensively used in crime-scene investigations to solve medico-legal cases in Forensic Medicine, especially in various ways and techniques in fingerprinting, DNA analysis, explosive detection, drug detection, and time since death estimation. Examination of body fluids, document analysis, explosive residual inspection, and nano-biosensors are benefited by nanotechnology. It is concluded by the review research on the use of nanotechnology that it is a more accurate, fast, reliable, secure system and an Armour for medico-legal investigations in Forensic Medicine. Keywords: Nanotechnology , DNA analysis, Forensic value, Forensic Medicine ,Nanoparticles

(Un)Reliable detection of menstrual blood in forensic casework - evaluation of the Seratec® PMB test with mock samples.

The identification of the type of body fluid in crime scene evidence may be crucial, so that the efforts are high to reduce the complexity of these analyses and to minimize time and costs. Reliable immunochromatographic rapid tests for specific and sensitive identification of blood, saliva, urine and sperm secretions are already routinely used in forensic genetics. The recently introduced Seratec® PMB test is said to detect not only hemoglobin, but also differentiate menstrual blood from other secretions containing blood (cells) by detecting D-dimers. In our experimental set-up, menstrual blood could be reliably detected in mock forensic samples. Here, the result was independent of sample age and extraction buffer volume. It was also successfully demonstrated that all secretions without blood cells were negative for both, hemoglobin (P) and D-dimer (M). However, several blood cell-containing secretions/tissues comprising blood (injury), nasal blood, postmortem blood and wound crust also demonstrated positive results for D-dimer (M) and were therefore false positives. For blood (injury) and nasal blood, this result was reproduced for different extraction buffer volumes. The results of this study clearly demonstrate that the Seratec® PMB test is neither useful nor suitable for use in forensic genetics because of the great risk of false positive results which can lead to false conclusions, especially in sexual offense or violent acts.

Amplification Failure of the Amelogenin X Gene Caused by a Rare Mutation in the Primer-Binding Region.

The study of gender markers is essential in forensic genetic analysis. Mutations in the X or Y homologs of the amelogenin gene can be misleading, resulting in serious mistakes in forensic genetic analysis. We recently discovered two male cases of the X homolog of the amelogenin (AMELX) allelic dropout while analyzing short tandem repeat genotypes obtained from crime scene evidence. Subsequently, we evaluated the molecular characteristics of AMELX allelic dropout in this study. We used two previously reported amelogenin primers to verify a half level of amelogenin gene amplification intensity in the two male cases, which we confirmed was caused by AMELX allelic dropout. We then characterized the point mutation using Sanger sequencing and designed mutation-specific primers that could overcome AMELX allelic dropout. Short tandem repeat genotyping analysis confirmed that the AMELX allelic dropout was recovered by the mutation-specific primer designed specifically for this case. The sequencing of the AMELX allele revealed a single-point variant from A→G at base position 7 downstream from the 3' end in the amelogenin forward primer-binding region. This point mutation was identically found in two different male cases, resulting in AMELX allelic dropout. To our knowledge, these mutations and the X homolog amplification failure of amelogenin have not been reported in the Korean population. Our study provides a reliable approach to AMELX allelic dropout due to rare case mutations and could enable the better interpretation of gender markers for forensic samples.

다공성 물질에서 인체 시료 채취를 위한 접착제의 적용

Many of the crime scene evidences are collected by transferring body fluids that are attached to the surface using a tool such as a sterile cotton swab or tape. The amount of body fluids transferred to the collection tool directly affects the possibility of DNA profiling. In this study, the recovery rate of body fluids and the detection rate of DNA profile were examined using sterile cotton swabs, rubber coating agents and urethane-based adhesives from porous materials. We prepared porous samples by spraying 100㎕ of diluted blood on their surface, each sample was collected using a sterile cotton swab, rubber coating agent, and urethane-based adhesive, and DNA recovery rates were compared. In the result, urethane-based adhesives showed the highest recovery rate of DNA with 68.6%. Rubber coating agent and sterile cotton swab showed 47.2% and 2.9% of recovery rate, respectively. Furthermore, we measured the FT-IR spectra of the rubber coating agent and the urethane-based adhesive and found that the peak of C=O group was larger in urethane-based adhesive. This result indicates that the polarity of urethane-based adhesive is greater than that of rubber coating agent and it has excellent blood wettability. As a collection tool, urethane-based adhesive had the disadvantage of taking a long drying time in the sampling process, however, it showed a high recovery rate when collecting body fluids from porous samples, and possibility for use in actual incident cases was confirmed.

Innovations in Forensic Sciences for Human Identification by DNA in the French Gendarmerie during the Last 10 Years

The IRCGN (Institut de Recherche Criminelle de la Gendarmerie Nationale) is a forensic science institute built by the French Gendarmerie which has the ability to exploit crime scene evidence. Any piece of evidence, anywhere in the world, in any environment, can be examined by IRCGN teams deployed in just a few hours. During the past 10 years, experts specializing in genetics have developed innovative genetic engineering technologies for application in forensic sciences. In this review, we highlight the main innovations and the creation of new tools for human identification, which are fully suited to the French Gendarmerie’s needs. Devices developed by the IRCGN are specific to the Gendarmerie’s purposes.

Contact Lens as Evidence in Crime Scene - A Way to Identify Gender

Contact Lens as Evidence in Crime Scene - A Way to Identify Gender

*e-mail: jez@unb.br Editor handled this article: Ivo M. Raimundo Jr. (Associate) Diffuse Reflectance FTIR of Latent Fingerprints and Discriminant Analysis for Sex Identification in Humans

Latent fingerprint is an important crime scene evidence, but it is not always recoverable or technically suitable for analysis with fingerprint patterns. Forensic science has shown that other information can be explored from traces using chemical compounds. Infrared spectroscopy is a nondestructive technique that is widely applied to a variety of forensic evidence. In this work, infrared spectroscopy and partial least square discriminant analysis were used to determine the human sex based on latent fingermark analysis. Fingerprint samples were taken from 42 male and female donors, then kept in either dark or light storage conditions, and the Fourier transform infrared (FTIR) spectra were measured considering a period of up to 30 days from collection. The regions from 3000 to 2800 cm-1 and 1790 to 1150 cm-1 presented the greatest differences in the peak intensities among the two sex groups. The results showed a correct discrimination rate higher than 80%.

Challenge to forensic podiatry crime scene report: Footprint-based gait analysis in homicide case revealed the perpetrator as the deceased victim's wife who was also the complainant

To identify the offender and unravel the mystery, physical evidence must be found at the crime scenes. When it is first taken from crime scenes, the relevance of some pieces of evidence is unclear or seems inconsequential, but as the investigation goes on, it seems to gain significance. Although footprints are a common physical indicator of a crime, including homicide, burglary, and sexual assault, they are frequently overlooked or dismissed as inconsequential during the early stages of an investigation. Currently, individual identification is done through gait pattern analysis based on footprints. A branch of forensic science known as forensic podiatry examines foot-related evidence in the course of a criminal investigation using specific podiatric knowledge, including the foot and lower limb. Analysis of footprints and gait is most consistent with other pattern-based forms of evidence, such as blood pattern analysis. Most cases of homicide and burglary involve the gait pattern evidence. Additionally, detectives frequently disregard crime scenes due to their familiarity. Science in podiatry is lacking. The current crime scene report, which was researched by the corresponding author (Prof. T. Nataraja Moorthy, henceforth referred to as "TN") in India, highlighted the importance of footprint and gait pattern evidence in a distinctive homicide crime scene. In India, a woman reported her husband's murder to the police, but a footprint-based gait pattern analysis proved she was the murderer, not the unidentified assailant. She committed murder while hiding the crime, which is known as "crime concealment".

POLICING FORENSIC EVIDENCE

POLICING FORENSIC EVIDENCE

산성인산화효소 검사법 (Acid Phosphatase Test)에서 정액예비시험용 시약 (AP Reagent)이 DNA 분석에 미치는 영향

Generally, DNA of crime scene evidence is obtained from body fluids such as blood, semen and saliva. The detection and identification of body fluids are the most important step in forensic investigation. Especially, the determination of semen is very significant in case of sexual violence. Prostatic acid phosphatase test as the presumptive test for searching presence of semen is commonly used because of its convenience and cost/time-effectiveness. In this study, we tried to figure out the effect of AP reagent on DNA analysis according to the time dividing into two groups, control and experimental (AP reagent reaction). The degree of DNA condition was evaluated by the DNA concentration, degradation index and STR analysis. The result of degradation index of experimental group is higher than the control group. Also, in STR analysis, peak height and peak height ratio (PHR) of experimental group is lower than the control group increasing the effect of AP reagent on DNA analysis over time. Therefore, we confirmed that it is necessary to be cautious using the AP reagent on the whole of forensic evidence for high-quality DNA analysis.

Precise and comprehensive determination of multiple body fluids by applying statistical cutoff values to a multiplex reverse transcription-PCR and capillary electrophoresis procedure for forensic purposes

Body fluid identification from crime scene evidence is an essential procedure in forensic investigations. Among various procedures, multiplex reverse transcription PCR assays have a clear advantage over conventional methods because different types of body fluids can be analyzed simultaneously. For more precise, comprehensive, and objective identification of forensically relevant body fluids, 15 target genes for blood, saliva, semen, vaginal fluid, and nasal secretion were selected; their primers were re-designed and multiplex PCR conditions were optimized to prioritize specificity for those body fluids. Multiple amplicons were separated and determined by the SeqStudio Genetic Analyzer with an all-in-one and easy-to-use cartridge. Then, the cutoff value was set for each marker to eliminate the detection of slight amplification in non-targeted body fluids. As a result, the targeted body fluid specificities of the developed procedure were drastically improved. Although successful determination of the target gene depends on sample condition and marker sensitivity, our procedure was applicable for the precise determination of body fluids in mixed body fluid stains, aged samples, and various mock casework samples. Therefore, it could be a powerful and convenient tool for the precise identification of multiple body fluids in forensic laboratories.

Survey on the investigation of forensic crime scene evidence

Determining and proving that a specific person or several persons may or may not be there at the Crime Scene (CS) in every criminal investigation are vital. Thus, in the law enforcement community, more often the physical evidence is collected, preserved, and analyzed. The accused cannot be predicted by normal people or judge just by looking at the evidence obtained at the analysis phase. So, research studies were undertaken on automated recognition as well as retrieval system aimed at forensic Crime Scene Investigation (CSI). A survey on the investigation of forensic CS evidence is depicted here. The main focus is rendered on the computer-centered automated investigation system. The latest research on the different evidence-centered Forensic Investigation (FI), such as the face, Finger-Print (FP), shoeprint, together with other Foot-Wear (FW) impressions, Machine Learning (ML) algorithm-centered FI, ML-centered pattern recognition, features of disparate evidence in forensic CSI, and various matching technique-centered FI, is surveyed here. Finally, centered on the accuracy and other two metrics, the methods’ performance for CSI is compared. Out of all the other methods, OLBP + LSSVM produced better results for precision and recall followed by CLSTM. In terms of accuracy, CLSTM produced better results than any other method.

Microbial DNA in human nucleic acid extracts: Recoverability of the microbiome in DNA extracts stored frozen long-term and its potential and ethical implications for forensic investigation

Human DNA samples can remain unaltered for years and preserve important genetic information for forensic investigations. In fact, besides human genetic information, these extracts potentially contain additional valuable information: microbiome signatures. Forensic microbiology is rapidly becoming a significant tool for estimating post-mortem interval (PMI), and establishing cause of death and personal identity. To date, the possibility to recover unaltered microbiome signatures from human DNA extracts has not been proven. This study examines the microbiome signatures within human DNA extracts obtained from six cadavers with different PMIs, which were stored frozen for 5–16 years. Results demonstrated that the microbiome can be co-extracted with human DNA using forensic kits designed to extract the human host’s DNA from different tissues and fluids during decomposition. We compared the microbial communities identified in these samples with microbial DNA recovered from two human cadavers donated to the Forensic Anthropology Center at Texas State University (FACTS) during multiple decomposition stages, to examine whether the microbial signatures recovered from “old” (up to 16 years) extracts are consistent with those identified in recently extracted microbial DNA samples. The V4 region of 16 S rRNA gene was amplified and sequenced using Illumina MiSeq for all DNA extracts. The results obtained from the human DNA extracts were compared with each other and with the microbial DNA from the FACTS samples. Overall, we found that the presence of specific microbial taxa depends on the decomposition stage, the type of tissue, and the depositional environment. We found no indications of contamination in the microbial signatures, or any alterations attributable to the long-term frozen storage of the extracts, demonstrating that older human DNA extracts are a reliable source of such microbial signatures. No shared Core Microbiome (CM) was identified amongst the total 18 samples, but we identified certain species in association with the different decomposition stages, offering potential for the use of microbial signatures co-extracted with human DNA samples for PMI estimation in future. Unveiling the new significance of older human DNA extracts brings with it important ethical-legal considerations. Currently, there are no shared legal frameworks governing the long-term storage and use of human DNA extracts obtained from crime scene evidence for additional research purposes. It is therefore important to create common protocols on the storage of biological material collected at crime scenes. We review existing legislation and guidelines, and identify some important limitations for the further development and application of forensic microbiomics.

Probabilistic genotyping of single cell replicates from complex DNA mixtures recovers higher contributor LRs than standard analysis

DNA mixtures are a common source of crime scene evidence and are often one of the more difficult sources of biological evidence to interpret. With the implementation of probabilistic genotyping (PG), mixture analysis has been revolutionized allowing previously unresolvable mixed profiles to be analyzed and probative genotype information from contributors to be recovered. However, due to allele overlap, artifacts, or low-level minor contributors, genotype information loss inevitably occurs. In order to reduce the potential loss of significant DNA information from donors in complex mixtures, an alternative approach is to physically separate individual cells from mixtures prior to performing DNA typing thus obtaining single source profiles from contributors. In the present work, a simplified micro-manipulation technique combined with enhanced single-cell DNA typing was used to collect one or few cells, referred to as direct single-cell subsampling (DSCS). Using this approach, single and 2-cell subsamples were collected from 2 to 6 person mixtures. Single-cell subsamples resulted in single source DNA profiles while the 2-cell subsamples returned either single source DNA profiles or new mini-mixtures that are less complex than the original mixture due to the presence of fewer contributors. PG (STRmix™) was implemented, after appropriate validation, to analyze the original bulk mixtures, single source cell subsamples, and the 2-cell mini mixture subsamples from the original 2–6-person mixtures. PG further allowed replicate analysis to be employed which, in many instances, resulted in a significant gain of genotype information such that the returned donor likelihood ratios (LRs) were comparable to that seen in their single source reference profiles (i.e., the reciprocal of their random match probabilities). In every mixture, the DSCS approach gave improved results for each donor compared to standard bulk mixture analysis. With the 5- and 6- person complex mixtures, DSCS recovered highly probative LRs (≥1020) from donors that had returned non-probative LRs (<103) by standard methods.

Analysis of Mass Number of Samples and Links Evidences Using DNA Finger Printing: Concludes act of Mob Lynching

Mob lynching is the heinous crime in the world by which a group of people kills the criminal or suspects of crime. In 2018 forensic science team facing the challenge of such horrible crime. Forensic Science Laboratory received a mass number of exhibits and analysis of this large number of exhibits was critical, complex and timeconsuming. Analysis of crime scene evidences recovered from suspects and biological samples of deceased along with their clothes were performed. Step by step analysis of these exhibits carried out by the detection of blood which minimizes the complexity of analysis and DNA profiling of these blood detected exhibits decreases the time cycle and increases the truthiness of analysis. DNA profiles obtained from a mass number of crime scene evidence and evidence recovered from suspects linked with DNA profiles of the deceased. This concludes the crime of mob lynching, uniqueness of the location and presence of a suspect at that time with the same location.

The effects of heat on the physical and spectral properties of bloodstains at arson scenes

This study examines the spectral characteristics of blood after being exposed to intense heat within a structural fire. Fire and intense heat have previously been understood to destroy or chemically change bloodstain evidence so that traditional forensic science recovery techniques are rendered ineffectual. Understanding the effects of the denaturation process and physical changes that occur to blood when exposed to heat may develop innovative forensic investigation methods, including the use of reflected infrared photography to enhance the recording of bloodstains. This research revealed that the denaturation of blood, specifically changes to the haemoglobin state from oxyhaemoglobin to methaemoglobin, resulted in the heat affected blood having a more optimal spectral target range within the infrared region when exposed to heat> 200 °C. It was observed both qualitatively and quantitatively using spectrophotometry, that there is a relationship between the appearance, viscosity and infrared absorption properties of blood when exposed to different temperatures as experienced in fire. This result indicated the increased potential for reflected infrared photography to be utilised as an effective tool for crime scene evidence recovery of bloodstains from arson scenes involving fire.

DNA Evidence as the Basis for Conviction

The sufficiency of DNA evidence alone, with regard to convicting accused persons, has been interrogated and challenged in criminal cases. The availability of offender databases and the increasing sophistication of crime scene recovery of evidence have resulted in a new type of prosecution in which the State's case focuses on match statistics to explain the significance of a match between the accused's DNA profile and the crime-scene evidence. A number of such cases have raised critical jurisprudential questions about the proper role of probabilistic evidence, and the misapprehension of match statistics by courts. This article, with reference to selected cases from specific jurisdictions, investigates the issue of DNA evidence as the exclusive basis for conviction and important factors such as primary, secondary and tertiary transfer, contamination, cold hits and match probability which can influence the reliability of basing a conviction on DNA evidence alone, are discussed.

Towards Forensic DNA Phenotyping for Predicting Visible Traits in Dogs.

The popularity of dogs as human companions explains why these pets regularly come into focus in forensic cases such as bite attacks or accidents. Canine evidence, e.g., dog hairs, can also act as a link between the victim and suspect in a crime case due to the close contact between dogs and their owners. In line with human DNA identification, dog individualization from crime scene evidence is mainly based on the analysis of short tandem repeat (STR) markers. However, when the DNA profile does not match a reference, additional information regarding the appearance of the dog may provide substantial intelligence value. Key features of the dog’s appearance, such as the body size and coat colour are well-recognizable and easy to describe even to non-dog experts, including most investigating officers and eyewitnesses. Therefore, it is reasonable to complement eyewitnesses’ testimonies with externally visible traits predicted from associated canine DNA samples. Here, the feasibility and suitability of canine DNA phenotyping is explored from scratch in the form of a proof of concept study. To predict the overall appearance of an unknown dog from its DNA as accurately as possible, the following six traits were chosen: (1) coat colour, (2) coat pattern, (3) coat structure, (4) body size, (5) ear shape, and (6) tail length. A total of 21 genetic markers known for high predicting values for these traits were selected from previously published datasets, comprising 15 SNPs and six INDELS. Three of them belonged to SINE insertions. The experiments were designed in three phases. In the first two stages, the performance of the markers was tested on DNA samples from dogs with well-documented physical characteristics from different breeds. The final blind test, including dogs with initially withheld appearance information, showed that the majority of the selected markers allowed to develop composite sketches, providing a realistic impression of the tested dogs. We regard this study as the first attempt to evaluate the possibilities and limitations of forensic canine DNA phenotyping.