Upon, or at any time after, the filing of such petition, the judge shall make an order for the appearance of any persons interested in the property, or any part thereof on or before the day of hearing therein stated, upon proof by affidavit either:

    1. That such person resides out of or is absent from the county, or his whereabouts unknown;

    2. That it cannot be ascertained in what county, state or country such person resides.