Physical evidence is always the most important requirement needed for the prosecution of criminals in court cases. It is in this essence that, evidence collection becomes an important aspect in law enforcement. The evidence presented in court for the prosecution of criminals ought to be of high quality for it to be fully relied on when making the ruling (Truro Police Department Manual, 2009, p.1). This can be achieved through proper identification and use of efficient laboratory equipment during evidence collection. In the case of a homicide where several evidences are required, the following methods will be appropriate in recovering the necessary evidence.
Blood forms the main physical evidence that is encountered in the case of a homicide thus it is very important to identify and type the blood for evidence. Being of biological origin, blood is prone to deterioration hence it requires careful procedures. The first thing is to determine the pattern of the blood stain by taking photographs or drawing sketches and documenting them. If the blood is already dried up, it could be scrapped off or cut out the stained objects for instance cupboards, carpet and clothes among others (Bureau of Forensic Services, 2002, p.1). As for the hand gun, it should be collected with the use of polythene collection bags so as to keep the finger prints intact. It could be checked for traces of blood, hairs, paint or any other tissues. The shell casings are required to be safely collected using polythene bags in order to avoid destroying the evidence. In the case of the hairs, hey could be photographed if they have not been firmly attached on an object. If attached, the object containing the hair is collected and taken to the laboratory.
Several tools could be used in evidence collection ranging from those used to physically locate the evidence to those used in transportation of the evidence. Some of the common evidence collection tools include: Collection tubes, evidence bags, cuticle sticks, sealing labels biohazard labels, crime scene barrier tape, gunshot residue collection, thermometers, hand preservation bags, evidence tags, permanent markers and metal scanners just to mention but few. The tools to be used in evidence collection normally depend on the type of crime and the evidence to be recovered from the crime scene.
After collection of the evidence, it should be properly packaged in order to maintain the evidence in its original state from the scene of crime. Packaging should be in such a way that it avoids contamination as well as minimizing chances of deterioration (DNA Initiative, 2003, p.1). Common ways of packaging include; wrapping and packing of the evidence in containers such as plastic ones, metal pillbox, powder boxes that should be sealed after packaging. In the case of blood, stains or swabs should be made and kept dry before taking it to the laboratory for analysis. Hairs could be packaged in druggist folds or even in the adhesive tapes. On the other hand, the handgun is packaged in constructed box in which the gun is securely held using a metal plate that is meant to block the muzzle.
Once the evidence is collected and packaged, it is taken to the laboratory where several tests are run to justify the crime based on the evidence. At the lab, physical tests could be done to determine the type of evidence. After which, DNA profiling is done on the biological evidences such as blood, hairs and any other fluids collected after which results are compared to the DNA profiles of the suspects(Hails, 2008, p. 143). Fingerprint screening is also done on the collected objects and compared to those of the suspects. All these done, the court will be in a position to make a justified decision.
Reference List
Bureau of Forensic Services. (2002). Physical Evidence Bulletin. Web.
DNA Initiative. (2003). Evidence Collection and Preservation.. Web.
Hails, J. (2008). Criminal Evidence. Cengage Learning. Print.
Truro Police Department Manual. (2009). Evidence Collection. Web.