This essay reviews the literature on criminal evidence. It examines the question of demonstrative evidence and its different types that are applicable in the court of law. According to the existing literature, any evidence given in a court of law is supposed to give credibility to a theoretical hypothesis in the form of a court case. In order to stand the test of credibility itself, the evidence must either be a direct type of evidence or disapprove any indirect evidences meant to destroy it. Prosecutors, investigators and advocates must, therefore, ensure that the evidence they present to the court is water-tight and can withstand any legal challenges. Furthermore, an attempt has to be made to make people understand the difference between hearsay and evidence based cases as this has posed a great challenge to timely and effective disposal of the cases before the courts of law.
Demonstrative evidence basically serves to illustrate or explain oral testimony to make it more of a tangible occurrence or event. For instance, science based evidence is typical of demonstrative evidence. When a pharmacist testifies that her patient succumbed to poisoning with lead, she will need to make reference to the graphical charts indicating the body of the patient showing how the poison travelled through the circulatory system. Such visual documents are essential to the credibility of the witness testimony of the pharmacist (Siemer, 1984). It is no longer a legal requirement that the court takes juries on time consuming trips to the crime scene to ascertain that a crime was indeed committed. Instead of a large number of evidence, backup evidence has become acceptable in the court of law. These could be photographs of the crime scene or videotapes capturing the actual incidence of the criminal act. And with the advancements of the scientific discoveries, scientific experiments and microscopic enlargements of tiny objects are considered admissible to sustain a case in the court of law. Besides, plaster casts like orthopedic casts are generally acceptable. Further, with the advancement of police investigation techniques, police composites, sketches and related mug shots are equally accepted. In addition, computer animations, maps and scale models are legible so long as they can stand the legal challenges directed at it (Kantor, 1998).
However, every evidence whether real or demonstrative needs to be authenticated. This means that it must be rightly identified as claimed by different components. For instance, real evidence may need to be authenticated by the specific witness who gave the testimony. They recognize a component of evidence as what the presenter of that evidence before the court of law claims it to be. On the other hand, demonstrative evidence has to be authenticated by a written document or some subsidiary evidence that supports its legibility. However, authentication of evidence must follow certain clearly laid down rules. For example, the obvious information conveyed by the authenticated evidence must not in any way change or distort the condition of the primary evidence significantly. A computer enhanced clip that makes a crime scene look lighter may actually be considered inadmissible before the court of law (Moenssens et al, 1995).