The party imprisoned or restrained may file a reply to the return and deny any of the material facts set forth in the return, and may allege any other facts that may be material in the case, which denial or allegation shall be on oath; and the court shall proceed promptly to examine the cause of the imprisonment or restraint, hear the evidence produced by any person interested or authorized to appear, both in support of such imprisonment or restraint and against it, and thereupon shall determine the matter according to law.