The Evidence Act 2001 (Tas) commenced in 2002. Evidence covers all the information given directly to the court by a witness or in the form of documents and of which the court takes notice because it complies with the ‘rules of evidence. The rules are as follows:
One of the requirements is that evidence must be relevant to the issue being tried. For instance, when a person is charged with theft from a house, it would be a relevant fact that their finger-prints were found on the windowsill of the house, whereas it would be considered irrelevant that they often consumed too much alcohol, or came from a family of thieves.
A witness will be asked to tell the court only what they saw or heard, not what someone else told them occurred (hearsay evidence). For example, a witness can say, ‘I saw X walk over and punch Y on the jaw’, but not, ‘I wasn’t there at the time, but B told me that he saw X walk over and punch Y on the jaw’. Whether a particular piece of evidence is hearsay or not is often a difficult question. It is a complex area of law subject to many exceptions at common law and under the Evidence Act.
In general, the opinion of a witness is not admissible unless the witness is an expert in the field on which the opinion is given. Thus, a doctor may be able to give an opinion on whether a particular blow may have caused the death of a person, while a non-medical witness cannot give such an opinion as evidence. Lay witnesses are able to give evidence on matters for which the ordinary experience of everyday life is sufficient, for example, speed of a vehicle, weather, handwriting, general identity and whether or not a person seemed drunk.
Generally, the prosecution cannot ask a defendant questions which tend to show that they are a person of bad character, or have committed other offences. But if the defendant, or their lawyer, attempts to attack the character of a prosecution witness by showing bad conduct by that witness the court may in turn allow the defendant (if they give evidence) to be questioned about their own bad character or conduct (Evidence Act, s104(4)). The defendant is entitled to raise their good character as an issue at their trial and to have such evidence taken into account on the question of their guilt or innocence. If they do so, however, the prosecution can call evidence which would tend to show that the defendant is of bad character if this is the case. A decision to attack the character of prosecution witnesses or positively raise the good character of the defendant always needs careful consideration.
Evidence is often given that the defendant made an admission or confession of guilt. The evidence may be of a conversation in which the defendant verbally confessed, or it may be a written record of questions asked by a police officer and answers given by the defendant (that is, ‘a record of interview’). In the case of serious offences, the interview of the defendant by police must be electronically recorded, usually by video. Any confession must be made freely and voluntarily for it to be admissible in evidence. It may not be admitted if it was induced by a threat or promise or an untrue representation made by the prosecutor or some person in authority.
The defence may object to the admissibility of a record of interview on this ground, and the magistrate will consider whether to admit it as voluntary or not. Even if the magistrate decides that the confession is voluntary, they may exclude it if it would be unfair to the defendant to admit it. The magistrate may also exclude the confession on the grounds of public policy. This involves weighing up the public interest in having offenders convicted, against the public interest in discouraging police officers from engaging in unlawful conduct during the investigation of a crime.