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Who is a witness?

A witness is a person who sees or knows something by personal experience. Legally it is defined as giving 'relevant evidence to a fact in issue'.

A witness can observe a person signing a document, they may have been present when a crime was committed, or when an accident happened.

They may also be experts in a particular field of study, such as psychiatry, sociology or drug pharmacology where they can be called to court to give their expert opinion within their field of expertise.

Witnesses in criminal matters

This topic is mostly concerned with witnesses in criminal matters.

A person may be a witness if they can verify that a person was at a particular place and at a particular time. This may be important to help prove that a person who has been accused of a criminal offence was somewhere else at the time and so could not possibly have committed the offence. This is called an alibi witness.

A witness may be called in to be questioned by police. They do not have to co-operate with police. They cannot be forced to attend an interview, answer questions or to make a statement.

Victims as witnesses

Victims are often asked to make statements to police and later to give evidence in court. If a victim makes a complaint to police about a criminal offence, the police will investigate. Part of this investigation involves getting evidence from witnesses. This is particularly important in family violence matters or sexual assaults where there may often not be many other witnesses to support the complaint.

Once a complaint is made the police decide whether to proceed with the matter and to press charges. The witness (complainant) can ask police not to proceed with the matter, but unlike in civil matters, once a complaint is made about a suspected crime, the victim does not have the power to force police to drop the charges. This is because criminal matters are 'crimes against the state'. This is different to civil cases, which are private matter between 2 or more people (or companies).

However a complainant can ask the police to withdraw their complaint. Thee is no guarantee that police will cease proceedings. This will depend on how much other evidence there is to support the police allegation that a crime has been committed.

See Statement of no complaint.

Giving evidence in court

Witnesses may also be required to go to court to give evidence. This may happen if they are subpoenaed, or otherwise ordered by a court. A subpoena is a formal legal document that summonses a person to appear before a court to give evidence as a witness or to produce documents.

A witness may be subpoenaed or issued with a witness statement on behalf of the prosecution or the defence. For example, if a person witnessed a crime being committed, they may be subpoenaed by the prosecution. If the witness is an alibi witness, they will be subpoenaed by the defence to help prove that the person accused did not commit the offence.

See Witnesses at court.

Family members

Sometimes a family member can be excused (on public policy grounds) from giving evidence against a family member. The aim of this is to preserve the relationship between family members. This will depend on the nature of their relationship.

See Witnesses and the accused.

Competence to give evidence

A witness must be competent before they can give evidence. Everyone is presumed to be competent unless evidence is produced to the contrary. A person will be found not to be competent if they cannot understand questions about facts or cannot give answers that can be understood, and if these problems cannot be overcome.

See s. 12—Evidence Act 2008 (Vic).

More information


Evidence Act 2008 (Vic)

  • s. 12—presumption of competence
  • s. 13—when person lacks competence
  • s. 18—family members

See Evidence Act 2008 (Vic).


Judicial College of Victoria

See Victorian Criminal Proceedings Manual—Witnesses—Chapter 13.