The value of the ancestral relationship is also significant. Consider that in CSR only a handful of actions are ever defined or understood resulting in many holes in our understanding of the incident. Effectively, in any CSR effort the analysis identifies a number of divergent chains of actions. Consideration of the causal chain often allows the analyst to develop some level of sequencing between divergent paths of actions and with that information understand if a particular hypothesis is supported or refuted. Axiom 12 — Any given set of actions will have a unique temporal relationship. Whereas causal connection between associated actions is more convoluted in explanation and recognition, temporal relationship is an unmistakable idea. The various interactions between objects that occur during any incident result in changes in state of the object – what we have described as actions. These actions occur at distinct points in space-time, a particular point on the object’s world-line. As discussed, spatial position can change, remain consistent, or be repeated, but temporal position is always unique to the given manifold. All of the objects the analyst is concerned with share the same manifold, thus their temporal values are uniquely related to one another.
gence.  Ever increasing complexity of systems and larger risks have motivated a growing body of accident investigation re- search by increasingly diverse disciplines. [3,4,5] Such research challenges much of the traditional wisdom and practices, and offers new investigation concepts, prin- ciples, and tools for the accident investiga- tion field.  Those new investigation con- cepts, principles, and tools diverge from the judicial ideas and practices toward a more scientifically oriented view of accidents and their investigation. What are those new de- velopments, and might they benefit crimi- nal investigations and crimesceneanalysis and reconstruction?
Given the limitations associated with the reconstruction process, it might well be argued that crimesceneanalysis is anything but “scientific,” and in fact such claims are often forthcoming in court. Often, in attacking an anal- ysis, opposing experts and lawyers imply that only the “scientist” can apply the scientific method; mere mortals such as analysts, investigators, and police officers are incapable of understanding or applying its mysterious tenets. In such arguments, one can be sure that the counselor will use great emphasis and intonation each and every time he or she uses the word “science.” More often than not, these individuals have no clue as to what the scientific method is or exactly what it entails. Nevertheless, by furthering this common myth, that it is something mysterious, magical, and beyond the average human’s understanding, they hope to prevent the presentation of critical information. So what is the scientific method and how does it relate to the crimesceneanalysis process? Can we really hope to understand and apply it to the inves- tigative process?
Simulated crimescene investigation is an essential component of forensic science ed- ucation, but its implementation poses challenges relating to cost, accessibility and breadth of experience. Virtual reality (VR) is an emerging technology which offers exciting prospects for teaching and learning, especially for imparting practical skills. We document here a multidisciplinary experimental study in which a bespoke VR crimescene app was designed and implemented, after which it was tested by both undergraduate student and staff/postgraduate student cohorts. Through both quali- tative and quantitative analyses, we demonstrate that VR applications support learn- ing of practical crimescene processing skills. VR-based practical sessions have the potential to add value to forensic science courses, through offering cost-effective prac- tical experience, the ability to work in isolation and in a variety of different scenarios. Both user groups reported high levels of satisfaction with the process and reports of adverse effects (motion sickness) were minimal. With reference to user feedback, we proceed to evaluate the scalability and development challenges associated with large-scale implementation of VR as an adjunct to forensic science education.
Given the large possibility of instruments that can be easily obtained and hence deliver blunt force injuries to the human skull, the authors decided to particularly focus on the possible Transfer and Saturation stain patterns formed at a crimescene as a result of assault particularly with blunt ended objects. Thus in a vio lent crimescene w ith sufficient amount of bloodshed, bloodstain pattern analysis often plays a significant role in proving or refuting the statements of the suspect, victim, bystander/eyewitness(if any) within the juridical setting. The stains along w ith the wound suffered by the victim/s could also be used for part/full reconstruction of crime scenes. These case studies particularly set out the background for this paper. On December 13, 2010, Dave Toplikar‘s report reinforced the importance of proper recording and hence interpretation of weapon transfer stains at a crimescene (Toplikar, D . 2010). Dave’s report in the Las Vegas Sun highlighted how the presence of a hammer imprint in blood pool was capable of influencing the decis ion of the jury and the fate of Mr.Edward Preciado Nuno, an ex-FBI special agent (Toplikar, D. 2010). While Daniel Holstein, senior crimescene analyst in Metro police and a certified expert in bloodstain pattern analysis, gave the case a new dimension by focusing on the hammer imprint that matched the size of the hammer that lay close to the apparent victim’s hand, Thomas Pitaro the defense attorney clearly marked out that the hammer imprint theory was not mentioned in the police report and was only added much later (Toplikar, D. 2010). There are two lessons to be learnt from the juridical proceedings of this particular case. Firstly, transfer stains often go unattended and hence unrecorded by most law e n f o r c e m e n t o f f i c i a l s . Secondly, when analyzed in relation to suspect, eyewitness testimony or other relevant circumstantial evidence, weapon transfer stains could actually give criminal jurid ical proceedings a new dimension (Toplikar, D. 2010), a new perspective.
While the scene creation techniques investigated produced some impressive results, it was considered that the amount of technical skill required to produce the scenes was so complex it would require a team of specialists, and such resources are rarely available. We preferred to have a system that would be fast, efficient and relatively cheap to use. Therefore an alternative had to be found. This was achieved with the use of a pre-created DirectX graphics engine for scene rendering, custom graphics developed in 3D Studio Max, and the development of a graphical application to orientate the objects when creating the scene. While this method is not as accurate as other techniques, it does offer some advantages. It is not always possible, or necessary, to create a photorealistic scene to evaluate and document the circumstances of a crime, and it would be very expensive to produce a virtual scene for every crime committed. In certain situations a method is required to quickly and cheaply create and render scenes. Examples of this are where the scene has been destroyed e.g. in the case of fire, or in areas that are in constant public use. It also appeared that the systems created previously had been over reliant on producing static photo- realistic scenes and had neglected the introduction of virtual animated characters. This is a drawback when the actions of the individuals are more important than the environment in which the incident occurred. Vital information and hypotheses can be evaluated when there are virtual characters acting out the crimes in front of the investigator rather than just motionless images. Therefore the following requirements for the system were identified:
Image enhancement is a key tool for forensic investigators when searching for evidence at a crimescene. It can be invaluable for evidence that is faint and tough to make out. It is usually necessary for investigators to be able to get rid of the background, which can be done by FFT or background subtraction. Investigators can use many different options for further enhancement, including gamma corrections, contrast stretching, and histogram equalization. By doing these following methods, forensic investigators can obtain the best possible evidence from a crimescene. Also the paper presents an overview of the different steps involved in the development of fingerprint based person identification and verification using minutiae based system .
The methods used by forensic laboratories have evolved so that very small amounts of biological material can produce a usable DNA profile. This, however, means that the potential for detecting DNA traces deposited by contamination at crime scenes becomes a factor. Contamination of any crimescene can easily occur if proper precautions, such as limiting the number of people inside the scene, are not taken. For example, first responders, emergency medical personnel, patrol supervisors, crimescene investigators, and medical examiners are all potential sources of contamination and/or loss of evidence.
Like most other areas of Forensic Science, bloodstain pattern evidence interpretation is characte- rized by the overlap from various other fields of science such as physics, computer science, medi- cal science etc. For example, fluid mechanics particularly explains the forces that lead to the for- mation of a particular bloodstain pattern. Forensic Medical practitioners particularly work to- wards drawing the correlation between the bloodstain patterns formed and the wound formed on the body or head of the victim concerned. The paper studied hammer transfer stains in particular because of the easy availability and usability of hammer round the world. Also we studied effect of stain pattern in the crimescene. The authors are of the view that of the different types of bloods- tain patterns, the most common stain patterns visible at the crimescene, particularly in the case where the victim is found to suffer blunt force injuries, are saturation, impact, cast off and transfer stain patterns.
The natural evolution of the study briefly described above was the investigation of the translational feasibility to real crimescene samples. As illustrated further in this paper, in preparation for the analysis of real forensic evidence, prelimi- nary consideration (followed by protocol development) was given to the collection, transport and storage of the crimescene marks under operational conditions; this also represents an advancement compared to previously published work and it is a significant one as lack of compliance with CSI require- ments prevents any analysis carried out using new and devel- oping technologies. For primary lifts, normally a CSI would seal them in acetate backing sheets for transport and storage of the evidence. Therefore a prior study was undertaken to assess the possibility to obtain both ridge detail and chemical information from fingermark lifts removed from acetate sheets which proved to be successful (data not shown). In the event that: (a) only secondary lifts were accessible, (b) the mark had been suitably photographed and the photo kept as primary evi- dence by the police or (c) the primary lifted mark was deemed to have no evidential value by the CSI who granted access to the mass spectrometrist, a system was devised to transport and store the lifts in a non contactless manner, avoiding con- tamination with debris, in an in house customised box, as shown in Fig. 1.
mark being strongly adhered to the surface, or a very old mark. The lifted mark was in any case subjected to MALDI MSI analysis. The analysis confirmed scarcity of fingermark residue material. No ion images of any minutiae could be retrieved and Fig 2C shows a representative example; this could also be ascribed to the surface being textured, which is an objective problem for conventional enhancement techniques too, due to physical distortion and interruption of the ridge pattern. Also, no useful molecular information could be obtained. It could be speculated that the mark had probably been subjected to high temperature on the light fitting, thus causing molecular thermal degradation. This is an example illustrating the limitations that the MALDI MS based methods may encounter with poor lifts and scarcity of molecular information, possibly due to severely aggressive environmental factors and age. The initial enhancement of mark (ii) was also poor and the CSI deemed the very little ridge detail recovered insufficient for an identification. The mark was therefore lifted, stored in the customised box and transported for mass spectrometric analysis. The acetate was peeled off and an optical image of the lift was taken before and after matrix deposition using a video spectral comparator. Although the ridge detail could not be improved in terms of quantity or quality upon MALDI MSI, probably due to an objective lack of ridge details, molecular information could be this time retrieved (Fig 3); in particular, endogenous species such as fatty acids, diacyl and tryacylglycerols were detected and identified on the basis of previous work 3,25 (data not shown). Figure 3A shows the molecular image of oleic acid at m/z 283.2 as example of this class of molecules. Interestingly, also a previously detected substance 12,16 was observed here at m/z 304.2. and 332.2 and these ions were used to generate molecular images of the mark (Fig 3B). These ions correspond to n-alkyl dimethylbenzylammonium (DMA) ions having 12 and 14 CH 2 repetition units respectively. n-alkyl DMA is a known
RESPONSE: The first deputy on scene secures and protects the scene while determining seriousness of the crime. If additional support is required to preserve the scene, a field supervisor is notified. Crime scenes may be secured by various means, such as: verbal commands, ropes or lines, blocking paths with vehicles or officer presence. A field supervisor may request the services of the Criminal Investigations Division (CID) and/or CrimeScene/Forensics Investigators if the scene is beyond the processing abilities of the field officers.
Many crimescene investigators and laborato- ries test for Touch DNA using either the wet/ dry swabbing or cutting methods [6,7]. When the swabbing method is utilized, the surface of the item is usually rubbed with a wet cotton swab, followed by a dry cotton swab in an ef- fort to collect possible skin cells. The wet/dry swabbing method is recommended for hard, non-porous items such as metal, glass or plas- tic, and can easily be performed at the crimescene with limited risk of contamination with exogenous DNA (e.g. from the person col- lecting the sample, or from nearby surfaces/ objects). The cutting method may be used for soft items, such as clothing, in which fabric from areas of interest is cut to collect possible cells. These two approaches can be success- ful on many items of evidence; however, they both have the limitation of placing unnecessary substrate (the cotton swab itself or the fabric cuttings) into the small DNA processing tube. There is a limited amount of substrate that can be placed in a tube, and the substrate itself may “trap” some cells during processing, decreas- ing the likelihood of obtaining results.
A database of 2660 known prints and 100 crimescene marks was used for ex- periments. Each known print has the meta data such as brand and model of the footwear, which is useful for linking a suspect’s footwear to a crimescene mark. In the clustered database, crimescene mark was first matched against every cluster representative to find the closest cluster, and then matched against each print in that cluster and the top n matches are retrieved. Retrieval results for 4 sample marks are shown in Figure 10.
ABSTRACT: Crimescene linking is a basic inference in criminal investigations. Links may be found when comparing all types of traces collected in different cases. The possibility of using fingermarks for crimescene linking has not been systemati- cally explored yet. Two different sets of data have been used in order to explore the potential of fingermarks to link cases: the content of the Swiss AFIS system and data collected by a regional law enforcement agency (canton de Vaud, Switzerland). The aim of this study is to provide data that can be used to design a methodology of how fingermarks can be used in forensic case linking processes.
The average DNA concentrations were slightly lowered by filter purification compared with the non-purified ex- tracts, except for touch stains and hair (Table 2). However, for both Amicon Ultra 30 K and Microsep 30 K the cal- culated DNA loss was only significant for the rape case samples (P-values <0.05) (see Additional file 1: Table S2). From the recovery rate study it is obvious that filter purification leads to substantial DNA loss. There, the recovery rates were determined applying highly purified DNA. When analyzing impure mock crimescene sam- ples, the removal of PCR-inhibitory compounds counter- acts some of the DNA loss through improved amplifiability, leading to smaller differences in the measured DNA con- centrations. For ten of the rape case samples and two samples of blood on kitchen paper, Quantifiler Human qPCR generated negative results with the crude extracts due to strong PCR inhibition (IPC not detected, results not shown). All of these samples generated usable DNA concentrations following purification using both Amicon Ultra 30 K and Microsep 30 K (rape case samples: 0.69 to 1.54 ng/μL for Amicon Ultra 30 K, 0.46 to 1.19 ng/μL for Microsep 30 K; blood on kitchen paper: 0.04 and 0.09 for Amicon Ultra 30 K, 0.09 to 0.10 ng/μL for Microsep 30 K).
and then to import it into the SketchUp crimescene. For this example, however, the authors used the Muryoung_Standard_Pose posable body found in the 3D Warehouse (search for “muryoung”) and reference photos from the scene to create a model of a body in the correct pose. The muryoung model was built in such a way that control points on the body may be used to pose it in the correct orientation and then these control points, which are on a separate layer, may be hidden in the final presentation (Figures 21 through 23). Some modellers prefer to work with models like this in a separate SketchUp file and then import them into their main crimescene model, as the authors have done here. Using separate files may also be useful if there are multiple people collaborating on creating one crimescene model.
During the commission of a crime, fibers are frequently left behind through cross-transfer from the suspect to the victim and/or the surrounding area. This type of evidence is characteristic of incidents involving personal contact which include, but are not limited to, murder, battery and sexual assault. Once collected from the crimescene, the forensic scientist must first identify the type of fiber before attempting to link it to a particular suspect or distributor. Although a fiber sample can tie an individual to a crimescene, this type of evidence does not have significant evidentiary value because most fibers are not unique and therefore cannot definitively incriminate a suspect. In most cases, they are used as supporting evidence to strengthen the case against a particular suspect.