An arrest occurs when the police have reasonable grounds to believe an offence has been or is about to be committed. Upon arrest, police take a person into custody and may charge them with a criminal offence. Not every person charged with a criminal offence will be arrested. The police may require a person to appear in court by either serving them an appearance notice at the scene of the crime or, at a later time, serving them with a summons.

Sometimes accused persons are kept in jail until they can appear in court. This might occur if, for example: