Scene Crime Processing - Term Paper Example

Scene Crime Processing] [Name] [Course] [Lecturer] [Date] A crime scene is any physical scene, anywhere, that is potential in providing evidence to an investigator. This may include a person’s body, building, vehicles, places in the open air or objects found in those locations. Crime scene examinations are undertaken whereby forensic or scientific techniques are used to preserve and gather physical evidence of a crime. The most fundamental principle of forensics is that every contact leaves behind a trace. This means that a contact of a person to another, contact of a person with a vehicle, or even a vehicle with a location can be used to trace some evidence (Martiny 2006). Evidence in crime scenes may include, biological samples from blood (DNA), semen, saliva and breath, hair, fingerprints, urine teeth or even body parts; fibers such as pieces of materials torn from clothing, pieces of weapons Brocken from the attack; photographs, videos, drawing and plans; documentary such as receipts, travel tickets or bank statements just to mention but a few (Martiny 2006). Crime scenes should be secure to avoid contaminations so as to allow adequate time to strategize the forensic examinations and this can be enacted by controlling access to scenes, covering scenes, keeping records of everyone who is having access to the scene (Jackson & Jackson 2007). Crime scene processing are the actions taken at the scene of crime or accidents which consists of the taking of photographs, preparing a sketch of a crime or accident scene, and the collection and preservation of physical evidence and are vital in gathering evidence of the crime. One thing that is of great concern to the scene technicians which is a big problem is crime scene contamination by curious officers, detectives and supervisors. The unintentional contamination of crime scene happens from evidence technicians, identification bureau officer, or laboratory specialist or even personnel who are responsible for processing of crime scene. Successful presentation of evidence from a crime scene depends on the ability to properly indentify evidence at the scene, handling it properly and proper documentation not to compromise investigations (Jackson & Jackson 2007). Evidence can be contaminated even before it is discovered and collected, by may be people getting back to the scene to access the damage. It can also be contaminated or even lost by exposure to the atmosphere and thus effective measures need to be implemented so as to avoid all this like sealing the samples in a tight container. The container may also be improper for handling samples. Forensic evidence should be handled with a lot of caution not to alter the results required (Martiny 2006). For instance, it is important to change gloves frequently and using disposable tools. If disposable tools are not available, then one must clean them completely before handling different peace of evidence. This is because if evidence is handled with a tool which was used to handle another one, then there can be a transfer of some evidence from the first item to the second and this may result to results which are misleading (Martiny 2006). Preventing contamination in samples is a very important factor that should be mastered. This is due to that, the integrity of the samples is what can prove guilt or innocence. There is precaution that should be adhered to before starting with forensic processing. First, one should look carefully at the scene carefully before even entering it. This will help in first taking the visual samples that can be seen in the entire site and take note of areas that would be having samples in the same area (Martiny 2006). Then enter the site and use the eyes to tell you of the samples to collect, wear gloves, face protection and eye protection, body protection so as to avoid any contamination to the samples. When picking up any hair or fiber samples use new, sterilized tweezers and this should be done to each individual sample. After the samples are collected they should be put in separate bags and sealed immediately. The tweezers should be discarded immediately to avoid reuse which will result to contamination (Martiny 2006). It is advisable to label the bag, include the date, time and the location of the sample and the name of the one who collected it. Incase of liquid samples, where there is the use of cotton wool, brand new should be used and a new tip for every sample. When performing lab tests, cleanliness should be observed for contaminations is also very high in this stage. Most importantly, it is vital to divide samples into several quantities soon after collection so that incase a mix up occurs, there will be backup samples to analyze (Stuart & Nordby 2009). When practical, physical evidence shall be processed at the scene of crime and released by signed receipt to the owner, evidence should be processed by the best available means. Precautions need to be taken to ensure that the evidence is not lost, destroyed, contaminated or altered during processing or collection and hence be contaminated. Evidence should be stored in clean unused containers as dictated by the type of evidence collected to avoid having then contaminated (Jackson & Jackson 2007). Caution need to be taken when dealing with evidence in the form of organic matter such as blood or tissue. In this case, there is need to use preventive measures or else decomposition will destroy this evidence prior to examination. Incase blood is involved, it can be allowed to dry in the air before sealing in on an airtight container. Wet or bloody clothing are also air dried and packaged in plastic or biohazard containers which are in accordance to P&E needs. Physiological fluid should be frozen, items supporting latent finger prints protected from nay movements or action that may destroy or contaminate the prints (Stuart & Nordby 2009). When these actions are accurately considered, then contamination of evidence will put but at bay and accurate result will be evident. The technicians should secure the scene, separate the witnesses, scan the scene, seeing the scene sketching the scene and finally search for evidence. Securing the scene means that people who are not authorized to enter the site are not allowed in and those who seem to be having some evidence are protected for later interrogations Houck, Jay & Siegel. 2006). Transfer, loss or contamination of evidence can occur in an unsecured area according to Locard’s exchange principle. Separating of witnesses in another important issue that helps curb evidence contamination; it is not allowed for witnesses to talk to each other. Their account of the event needs to be compared (Kemp & Smith 2005). When separation is done, they will not collude and therefore it is possible to gather much more information about the occurrence. Scanning the scene is equally important. This is done to determine where the photos should be taken. This is where it is done considering the primary crime scene and secondary crime scene. For example, a bank robbery may be a primary crime scene and the home of the suspect the secondary scene. This will allow accurate gathering of evidence. Seeing the scene is also important, photos of the overall area and close up photos with or without a measuring ruler should be taken (Kemp & Smith 2005). The sketching of the scene is important for noting the position of the evidence. Finally when all this is said and done, then searching of evidence is done to search each and every area for evidence This is where vacuum cleaners can be used to collect evidence or even adding lighter source so as to see more samples. The evident collected need to be secured for as long as it is in the hands of the technicians; maintaining the chain of custody is very important. After the evidence is identified and put in the container it is clearly marked and put in the collection bag which is labeled with pertinent information, sealed and collector’s signature written on the seal edge (Kemp & Smith 2005). Then the container is given to the one responsible for its care. Then it is handed over to the lab technicians who open it for examination in another area rather than the sealed edge. After the examinations are completed, the technician repackages the evidence with its original packaging, reseals in a new packaging and signs the chain of custody log attached to the packaging (Houck, Jay & Siegel. 2006). This ensures that the information is responsibly handled from the crime scene to a courtroom without alterations or contaminations. When this is implemented throughout the evidence processing, contamination is going to be curbed and justice found eminently Conclusively, evidence contamination has been a headache for many investigators for it regularly occurs altering the resulting and apparently resulting to wrong judgments. It is ve4ry important for the forensic science disciplines especially those handling the DNA identifications to analyze samples to do so in all means that will prevent contamination. Clean techniques in the laboratory techniques should be always used so as samples can be prevented from contamination. Technicians are advised to wear disposable gloves between every sample collected and always wear masks when dealing with saliva and mostly especially when they have cold or are prone to allergies. Disposable tools to collect evidence should be always being encouraged and where budgets can’t support that they should breach and sterilize their instruments between each collection. When dealing with a crime scene, people should not be allowed in the secured parameter. If extraneous people have to enter the scene, then they have to be escorted by someone who is working in the scene to make sure that they will not destroy any evidence or leave any worthless evidence. Eating, drinking or smoking in the site is also prohibited so as to protect evidence. Also, investigators should also be protected from intruders who may not like the whole activity. References Jackson, Andrew R.W. and Julie M. Jackson. 2007. Forensic Science 2nd Ed.. Pearson. USA James Stuart H., Jon J., Nordby. 2009. Forensic Science: An Introduction to Scientific and Investigative Techniques 3rd Edition CRC Press: USA. Kemp, B., M., Smith D., G., 2005. Use of bleach to eliminate contaminating DNA from the surface of bones and teeth. Forensic Sci Int 154: 53-61. Houck M., M., Jay A. Siegel. 2006. Fundamentals of Forensic Science. 2nd Ed. Elsevier Science. Martiny, J., B., B., J., Bohannan, J., H., Brown, R., K., Colwell, J., A., Fuhrman, J., L., Green, M., C., Horner-Devine, M., Kane, J., A., Krumins, C., R., Kuske, P., J., Morin, S., Naeem, L., Ovreas, A., L., Reysenbach, V., H., Smith, J., T., Staley, 2006. Microbial biogeography: putting microorganisms on the map. Nat. Rev. Microbiol. 4:102-112 Read More