The Taxonomic Classification system for bloodstains is the established set of principles or laws for placing bloodstains in categories according to their shared traits. The shared characteristics vary in terms of degrees and tend to have a hierarchical relationship. The Taxonomic classification system for bloodstains is hierarchical in the sense that broad categories are found at the top and more refined categories are found while moving down the criteria. This makes the conclusion concerning a particular classification of bloodstains more unique (James, Kish, & Sutton, 2005). The system is crucial because it shapes the future of bloodstain pattern analysis, which is expected to be based mainly on the description. Additionally, the system is sustained by the bloodstain pattern analysis, where experts have developed the classifications for bloodstains using a taxonomic approach.
An objective approach is essential to use when classifying bloodstains because it is crucial in the processing of physical evidence in a crime scene (Tom & Ross, 2008). Bloodstain pattern evidence is part of the physical evidence, which is any large or small particle that tends to disprove or prove a point in question. An objective approach is also crucial because bloodstains classification considers physical features like concentration, shape, size, distribution and location. Objectivity is valued because once bloodstains are classified, they can be used in the reconstruction of a crime, help in pointing out the participants, and discrediting or confirming an alibi.
Taxonomic classification is one step in the objective approach towards bloodstain pattern analysis as it presents the ground for an analyst to define the origin of an event more effectively. Taxonomic classification and objectivity bear more importance in crime scenes involving sexual assaults and homicides since there is a lot of physical evidence, especially that of bloodstain patterns.
There are different kinds of DNA that may be left deposited at a crime scene area. These kinds of DNA include the biological sources which contain cells that can identify DNA. The types of DNA include blood, tissue, sweat, hair, dandruff, mucus, saliva, ear wax, vaginal cells, and semen. To examine the type of DNA different methods of analysis are used such as the Mitochondrial DNA, Y-Chromosome tests, Polymerase Chaim Reaction (PCR), and Short Tandem Repeats (STR) (Butler, 2010).
For hair, semen, and blood kinds of DNA, the mitochondrial DNA analysis can be used such that it analyzes the DNA according to the mitochondrion part of the cell. Additionally, the mitochondrial analysis is suitable for remains that are old and for cells that lack a nucleus, like teeth and bones. Best for semen and vaginal cell DNA examination is the Y-Chromosome analysis since the chromosome of passed directly from the father to every son. Therefore, Y-Chromosome analysis is useful in tracing the existing family relations among men (Saad, 2005). The short tandem repeat analysis is helpful in examining specific parts of DNA for the purpose of discriminating between two DNA profiles. The Polymerase Chain Reaction is useful in analyzing skin cells and blood.
Some of the crime scene circumstances which affect successful coding of the DNA include crime scene integrity (during the documentation of evidence as presented on the crime scene), crime scene contamination, chain of custody of evidence acquired, and the storage and transportation of evidence from the crime scene.
For latent fingerprints contained in windows, an alternate light source can be used by investigators for examination. Alternative light sources are LED or laser devices that emit a certain spectrum or wavelength of light. Others have different filters that produce various kinds of spectra which can either be processed with powder or be photographed. To identify the latent fingerprint in a window, a florescent dye stain can be applied on the window, followed by the use of an orange source of other light. This will make the latent print become more visible for documentation.
For a firearm, fingerprint dusting can be done using a latent print powder. The dusting simply involves the application of particles that are finely divided and physically stick on oily parts in latent prints found on a non-porous surface such as on the surface of a firearm. Once the powder adheres to the latent print residue, the fingerprint detail will be more defined and there will be enhanced visibility (Hawthrone, 2008). There are two key elements that provide adhesion to the latent print residue without having to paint the substrate, which is the binder and pigment.
For a dark glass beer bottle, latent fingerprint processing can be done using cyanoacrylate processing. Otherwise known as superglue processing, it involves fuming a surface prior to applying stains or powders. This is a suitable process for a non-porous surface such as the dark glass beer bottle, which consists of having the object being exposed to the cyanoacrylate vapors (Shaler, 2012). Then, the vapors stick to any prints which are present on the object, giving them the chance to be viewed using both a white light source or an oblique ambient light.
For a note with an address written on it, chemical developers can be used. The chemical developer is necessary because the note is a porous surface, is processed using typical chemicals such as physical developer and ninhydrin to make the fingerprints visible. Once the chemical developer is placed, specific components, such as the inorganic salts and amino acids, of the residue of the latent print react. Ninhydrin makes the prints to acquire a purple color that allows them to be photographed easily.
One case law concerning the admissibility of digital photographs in the courtroom is English v. State of Georgia 422 s.e.d2d 924 (September 28, 1992, Court of Appeals of Georgia). The facts of the case include an undercover agent videotaping a sale of cocaine, and the videotape was digitized and the defendant’s images were taken through computer enhancement before being printed as single pictures. The videotape’s copy was presented as an exhibit at the trial. The issue concerned whether the court made an error in submitting an image that is computer-enhanced. The ruling on the case was that the computer-enhanced picture was appropriate since it was a fair and accurate representation of what appeared in the copy of the videotape.
The case law above illustrates how digital evidence can be received in the criminal process and is one among many cases where digital evidence has led jurisdiction successfully. Additionally, there are many other cases which have presented valuable information to the court in terms of evidence which would not have, by other means, been evidence. Digital photographs as well as other kinds of technology, like audio enhancement, forensic video analyses and enhancing fingerprints using digital means, have assisted the court in achieving more diverse evidence.
For digital photographs to be accepted in courts, as in the case above, the court needs to be convinced that the evidence is a worthy reception to the criminal proceedings. The admissibility of digital photographs also depends on the competence and qualifications of the expert in charge, the knowledge and skill of the prosecutor dealing with the evidence and the quality of the evidence that is presented. Many jurisdictions in Canada and the US have been led successfully over the previous decade using digital evidence.