Forms of Evidence with an Objective Existence - Essay Example

Forensic Evidence Analysis of the reasons why such a high proportion of evidence is of no value in volume and major crime 1. Introduction Evidence can be divided into two broad types. Testimonial evidence is given in the form of statements made under oath, typically in response to questioning. On the other hand, physical evidence is any form of evidence with an objective existence, which is anything with size, shape, and dimension. Physical evidence can take any form. It can be as huge as a house or as small as a fibre. It can be as short-lived as an odour or as noticeable as the scene of an explosion. In fact, the assortment of physical evidence that may be encountered in an investigation is unlimited. In a UK study, physical evidence forms a third major source for pinpointing a suspect or substantiating his or her presence at the scene. Considering the fact the physical evidence in an investigation is infinite, only some of these are of real use or value and majority of materials from the crime scenes is disposed. The reason why such a high proportion of evidence is of no value in volume and major crime is the subject of our analysis. 2. Physical Evidence Gathering The aim of crime scene investigator should be not to ignore anything providing significant information, which may contribute to solving the crime under investigation. There are many variety of physical evidence that do not lend themselves to statistical evaluation as it is not the volume of data presented that would support an estimate of the frequency in which a particular type of physical evidence might be encountered. A successful crime scene investigation is judged by the outcome obtained. A crime scene investigator must recognize, gather, and make use of every piece of physical evidence that may be present while recognizing that helpful evidence could be hiding somewhere among a multitude of worthless materials (Newburn et. al. 2007, p.244). 3. Nature and Value of Physical Evidence The nature and value of physical evidence can be classified into two. These are evidence with class characteristics only and evidence with individual identifying characteristics. The first one are those evidence, no matter how thoroughly examined, can only be place into a class. A definite identification can never be made since there is a possibility of more than one source for the material found. For instance, single-layered paint, such as from a safe or car, soil, glass fragments too small to match broken edges, hairs and fibres, etc. The other one is evidence that can definitely be identified with a person or source if sufficient microscopic or accidental markings are present such as fingerprints, handwriting, bullets, tool marks, shoe prints, pieces of glass where broken edges can be matched, and wood where broken/cut surfaces can be matched (Hunter and Cox 2005, p.170). 4. The Need to Gather Sufficient Evidence from the Crime Scene In forensic investigation, adequate materials should be gathered. Considering the amount of sample to collect is basically an issue of familiarity. As a universal rule, however, as much material as is practically possible to collect should be taken. Usually, it is unfeasible and sometimes impracticable to return to a crime scene later to collect more material if more evidence is required. Thus, generally, more is better than less (Fisher 2003, p.11). Forensic evidence starts at the scene. If evidence is overlooked or inappropriately taken cared of at the scene, no amount of laboratory analysis or processing will be able to correct the problem and the scene typically cannot be revisited to have another attempt at acquiring further evidence (White 2004, p.21). In a fire scene for instance, there are two rules to bear in mind when collecting specimens for laboratory analysis. For every solid sample collected, a comparison sample must be taken as well. If comparison samples are not taken, and an accelerant is detected in one of the removed samples, the investigator has no idea whether the accelerant was inherent in the material or not. A good example is turpentine in pinewood. Turpentine is a natural component of pinewood and testing results will reveal this reality. A second rule for the collection of solid sample is that only one type of material should be isolated and collected per container. For instance, if the area of origin, a hardwood floor is covered by linoleum and the linoleum is covered by carpet, at least six or possibly eight samples may need to be taken. One samples each of the carpet, the linoleum, and the hardwood floor at or near the area of origin plus three comparison samples. If the carpet has a padding material, a sample of the padding should be taken from the area of origin as well as a comparison sample. When collecting the samples, if a sample cannot be separated and the padding has melted into the carpet, four comparison samples, each containing a single specimen per container, should still be taken. If several points of origin are found during an investigation, the number of samples removed can easily number a dozen or more (Girard 2007, p.38). 5. Quality and Quantity of Evidence Presented with a crime scene, police investigators and technicians collect and present evidence to the forensic scientist for assessment and interpretation. In a normal situation, it represents a partial picture of the evidence that was left behind in the scene of a crime. This is because investigators cannot distinguish everything and they cannot collect everything. At worst, it represents evidence collected in accordance with a particular predetermined hypothesis that police investigators are seeking to strengthen. Frequently, this is done together with disregarding or purely ignoring facts and evidence that might direct the forensic examiner away from the desired conclusion. The forensic examiner is given what attorneys and investigators consider of importance to their case and often nothing further. Quantity and quality of the evidence aside, what is collected and subsequently considered evidence can and does have an impact on the subsequent examination (Chisum and Turvey 2006, p.58). In contrast, unlike the vast majority of practicing scientists, many forensic examiners have no control over the quality or quantity of their evidence. Depending on the abilities of local crime scene personnel, the quantity of evidence collected will differ considerably. In some occasion, the examiner will have loads of evidence to check and may find the sample sizes less than desirable sometimes to the point where no significant examination or testing can be performed. With regard to the quality of evidence, forensic examiners must regularly perform forensic assessments on physical evidence that is of substandard quality. The quality of evidence can be compromised by a variety of agents or circumstances. The very nature of the evidence may prohibit meaningful interpretation (Chisum and Turvey 2006, p.59). Normally, quite a few hundreds of items arrive at the laboratory and the forensic scientist must decide which it would be most beneficial to examine, and for what. If all items were to be examined and in all aspects, a single case could turn into a lifetime’s work. Selection made at this stage depends on the experience and on the amount and quality of the information scientist has received about the case. Decisions at this stage can significantly influence the quality and value of the evidence later produced (Walker and Starmer 1999, p.123). 6. The Impact of Locard’s Principle on the Volume Evidence Another reason why the volume of evidence increases in forensic examination is probably due to the commonly employed principle that material traces are left behind when someone handle something or when things rub together. This principle is better known as the Locard’s Principle. For instance, fingerprints are used to link a person with a place or object, such as bank vault or gun. Blood on a suspect’s clothing is used to link the victim with the suspect. Similarly, traces of hairs, fibres, paint, glass, and soil are used also to establish that a person was exposed to an object, a place, or another person (Newburn et. al. 2007, p.323). For this reason, almost all items in a crime scene are subject to forensic examination thus volume of material in forensic laboratory increases. After thorough analysis, some or majority of these items will yield no evidential value and cannot be use in court. Evidence admissibility in court is a very important factor to consider in forensic science thus any material collected and analysed that has no evidential value must be disregarded and disposed. 7. The Impact of Mishandling and Contamination of Evidence One issue of concern is evidence mishandling and data-recording errors. The sophistication of the evidence-handling process lends itself to disaster unless those persons managing the evidence are careful. Mix-ups and mislabelling of biological sample, trace evidence, or results can take place at any point from the time of collection at the crime scene to the writing of the final report. Unnoticed mishandling of evidence can cause false matches, while the analyst might have determined the genetic types of the samples accurately; the inferred connections between the samples can be erroneous because of sample mix-up. Sample mishandling and erroneous recording of data can occur with any kind of physical evidence and are of great concern in all fields of forensic science. The matter regarding mishandling is compounded by the actuality that most forensic laboratories have little or no control over the handling of evidence elsewhere (Pyrek 2007, p.314). Crime scenes are often approached with the outlook that what is unfamiliar to the scene is of value and that if it is usually present, it does not really have any great importance. Items normally present in an assault scene for instance often are not categorized as known samples, thereby denying the forensic examiner the opportunity to relate recovered fibres to the suspect. Forensic science is a study of comparison between known and unknown samples thus having more known than needed is far better than not having what is essentially required. Regardless of what evidence is available, despite what its characteristics, it is only be considering all evidence and the context in which it is located that solutions to crime are found. Thus, every piece of available evidence in a scene has a purpose and the crime scene technician cannot afford to chaotically gather or preserve it. It is exceedingly important that evidence be collected correctly or all its value may be lost. The rising sensitivity of the analytical instrumentation used in contemporary crime labs means that a great deal more information can be acquire from physical evidence. It also means that there is a much greater probability that contamination of the evidence can render it worthless. Contamination can come from the investigator or the environment or can be cross-contamination from other evidence. When the value of physical evidence diminishes due to contamination, the laboratory has no option but to dispose them since it cannot be use as evidence in court (Auburn 2000, p.87). 8. Conclusion Physical evidence is anything with an objective existence thus anything present at the crime scene that could help solve the crime is subject to forensic investigation. However, only some of these materials will yield elements that could sufficiently link a suspect to a crime thus a high proportion of materials gathered at the crime scene are disposed. Forensic investigators generally consider the fact that it is impractical to return to the crime scene on later time thus they gather more physical evidence to ensure that all possible evidence are included. Another reason why forensic investigators gather more is the need to acquire a comparison sample. Forensic is a study of comparison between known and unknown samples thus it is always better to have more than what is actually needed. The quality of material delivered to the laboratory is another reason why a high-proportion of physical evidence is discarded. Forensic examiners frequently have to deal with substandard physical evidence that would prevent them from giving meaningful interpretation. Forensic examiners have no control of over the quantity or quality of evidence delivered in the laboratory and must decide which would be most advantageous to examine. Finally, most forensic examiners believe in the Locard’s principle where material traces are left behind when someone touches something thus all items in a crime scene are examined. However, since only a few of these items actually have evidential value, majority of them will be disregarded and disposed. 9. Bibliography Auburn Jonathan. 2000. Legal Professional Privilege: Law and Theory. Hart Publishing, UK Chisum W. Jerry and Turvey Brent E. 2006. Crime Reconstruction. Academic Press, UK Fisher B. 2003. Techniques of Crime Scene Investigation. CRC Press, UK Girard James. 2007. Criminalistics: Forensic Science and Crime. Jones & Bartlett Publishers, UK Hunter John and Cox Margaret. 2005. Forensic Archaeology: Advances in Theory and Practice. Routledge, UK Newburn Tim, Williamson Tom, and Wright Alan. 2007. Handbook of Criminal Investigation, Willan Publishing, UK Pyrek Kelly. 2007. Forensic Science Under Siege: The Challenges of Forensic Laboratories and the Medico-legal Death Investigation System. Elsevier Academic Press, UK Walker Clive and Starmer Keir. 1999 Miscarriages of Justice: A Review of Justice in Error. Oxford University Press. UK White Peter. 2004. Crime Scene to Court: The Essentials of Forensic Science. Royal Society of Chemistry, UK Read More