(b) Content. The affidavit shall fully and explicitly state whether
the person detained is or has been in the custody of the person to whom
the writ is directed, the authority and cause of the detention, whether
custody has been transferred to another, and the facts of and authority
for any such transfer. A copy of any mandate by virtue of which the
person is detained shall be annexed to the affidavit, and the original
mandate shall be produced at the hearing; where the mandate has been
delivered to the person to whom the person detained was transferred, or
a copy of it cannot be obtained, the reason for failure to produce it
and the substance of the mandate shall be stated in the affidavit.