At the hearing on the return of the writ, the petitioner may, on oath, deny any of the material facts alleged in the return, or allege any fact to show either that the imprisonment or detention is unlawful, or that the petitioner is entitled to discharge. The judge shall proceed, in a summary way, to hear allegations and admit relevant evidence in support or against imprisonment or detention and, at the conclusion of the hearing, dispose of the petitioner in accordance with law.