Bail allows a person charged with a crime to be released before their trial, as they are innocent until proven guilty. Bail can be granted at the police station, in a bail hearing, or at a preliminary hearing. A surety, like money or a guarantor, may be required to ensure the person attends court. Bail can be refused if the person is charged with serious crimes like murder or treason, is already in custody, is deemed a risk to public safety, or may interfere with witnesses. Those refused bail are held on remand until their trial.