If the challenge is to the authority for confinement, the petition shall state, in substance:
(1) That the party in whose behalf the writ is petitioned is imprisoned or restrained of liberty, the place where, and officer or person by whom the party is imprisoned or restrained, naming both parties if their names are known, or describing them if not known.
(2) That such person is not imprisoned or restrained by virtue of any order, judgment or process specified in ORS 34.330.
(3) The cause or pretense of the imprisonment or restraint, according to the best knowledge or belief of the plaintiff.
(4) If the original imprisonment or restraint is by virtue of any order, warrant or process, a copy thereof shall be annexed to the petition, or it must be alleged that, by reason of the removal or concealment of the party before the application, a demand of such copy could not be made, or that the demand was made, and the legal fees therefor tendered to the person having the party in custody, and that a copy was refused.
(5) That the claim has not already been adjudged upon a prior writ of habeas corpus, to the knowledge or belief of the plaintiff.