When investigating a crime, the police may question anyone.

It is a fundamental principle of criminal law in Australia that a person may remain silent and refuse to answer all questions put to them. Legal advice should be sought before answering any questions.

There are some important exceptions to this rule that require a person to answer certain questions. These exceptions can apply whether or not the person is a suspect or has been arrested or charged with an offence. These exceptions include:

These exceptions are explained further in the pages that follow.

It is best to cooperate with the police, be polite, answer the questions that must be answered, and not answer any other questions. Police will usually indicate which questions must be answered. A person may ask police if unsure.

If there is anything a suspect wants to tell the police, such as an alibi, they should first talk to a lawyer so that the lawyer can help provide the information to the police. It is a good idea to give that information (especially about an alibi) to police as soon as possible after getting legal advice so that it does not look like it has been invented later.

Questioning at a police station without arrest

Police often ask people to accompany them to a police station. This is only an invitation. The police can only force someone to go to a police station if they are under arrest.

A person who refuses to go with the police may be arrested and charged, and taken into custody, only if the police reasonably suspect that person of committing or having committed an offence, or of being about to commit an offence [Summary Offences Act 1953 (SA) s 75]. Otherwise the police cannot lawfully detain the person.

Detention without making a lawful arrest is false imprisonment for which the police can be sued. It may also mean evidence obtained is excluded from evidence in a trial.

Passwords and pins

There is generally no requirement to provide a password, pin or code to unlock or access a mobile phone, computer or other electronic device or an app or software held on such a device. Police usually need a court order to compel a person to provide their password or pin. Of course, police may be authorised to seize and search an electronic device (for example, under a general search warrant [Summary Offences Act 1953 (SA) s 67]) and may not need the password or code to access data.