In a criminal trial the prosecution convicts a defendant by proving the elements of the offence. These elements must be proved by adducing evidence. To ensure the evidence put forward against a defendant is of high enough quality there are rules which control what evidence can and cannot be used.
In Queensland these rules are found both within the Evidence Act and within the common law, or previous decisions of the courts. Depending on the type of evidence and the circumstances surrounding the evidence different tests are applied by the court to determine if the evidence is admissible or inadmissible.
Relevance
Firstly for evidence to be considered admissible in a trial or hearing it must be considered relevant to one of the facts in issue. In a criminal trial this means it is relevant to an element of the offence. If evidence is not relevant to any element of the offence it will not assist the court with the progression of the trial and is therefore deemed inadmissible.
Legally Admissable
The second test evidence must pass to be deemed admissible is it has to be legally allowed to be put forward in court. This test takes into account a wide variety of factors such as the form of evidence, the manner in which it is presented to the court, the manner in which it was obtained and who is presenting it to the court.
Forms of Evidence
Evidence itself can take many different forms. These different forms are divided into the three categories of oral testimony, documentary evidence and real evidence. Oral testimony involves a witness verbally giving evidence from the witness box and being cross examined by opposing counsel. Documentary evidence is a broad term that includes written documents as well as drawings, labels, maps, photographs, discs or tapes containing sound recordings and films, negatives or tapes containing visual recordings. Real evidence refers to all evidence that is not considered oral testimony or documentary evidence. An example of real evidence would be fingerprint evidence gathered from the scene of a crime.